Quiet environment is essential for improving quality of living and rest. For example, noisy neighbors degrade quality of sleeping of residents. Due to emphasis on energy saving of buildings, more insulation and tighter sealing is applied for windows, doors, and walls of new buildings. As results, not only energy dissipation of new building is reduced, but also interior of new buildings have become significantly quieter. However, sound and heat insulation performance of existing buildings is relatively worse, when compared to that of recent buildings. As elapse of time, gap between bricks or concrete of building and sealing grows larger, worsening of sound and heat insulation performance of buildings is unavoidable. To provide quiet room for quality control of products or other purposes in noisy environment, indoor noise chamber is required in practice. In present work, sound transmission through indoor noise chamber is measured using different noise sources. For the worst case, noise source and sound transmission of door slam noise is shown.

It is important to increase the sound proof performance of building for reduction the influence of aircraft noise on the basic of actual survey of existed buildings. The purpose of this study is to propose the sound proof method about indoor noise of a movie theater due to aircraft. In this study, field measurement of aircraft noise level difference were carried out for 5 type aircraft. As the result, aircraft noise levels showed to be 83.6∼98.3dB(A) and indoor noise level were NC-50∼NC-65 over acceptable NC-30 in a movie theater. Noise reduction effect showed to be NC-15∼NC-30 in a movie theater.

Railway noise is one of the main causes of environment impact. Whenever a new railway line is planned or a housing project near an existing railway is proposed, an estimate of the relevant noise levels is usually required. For this, it is necessary to quantify those parameters that affect the railway noise. Therefore we investigated the noise level which subway trains generated passing through the block of test railway track between Hopo and Keumgok station in Busan. This paper shows the status and characteristics of the subway train noise and a subjective evaluation.

본 연구에서는 실내 음 환경 개선을 주목적으로 식물의 실내소음저감에 관한 연구로, 챔버 내 상록 피침형 관엽수종인 아라우카리아를 배치한 후 실내음향 파라미터를 이용하여 음향특성을 분석한 결과는 다음과 같다(Fig 2, 3, 4). 아라우카리아 식재에 의해 실내 잔향시간, 흡음률에 있어서 뚜렷한 개선효과를 나타내었고, 흡음성이 높은 종이 재질 구조물의 흡음률과 비슷한 수준을 보였다. 특히 고주파 대역으로 갈수록 그 효과가 좋았던 결과에 따라 실내 식물배치에 의한 주파수 대역별로 부분적인 소음저감효과를 기대할 수 있을 것으로 판단되었다. 식재의 배치방법을 달리하여 잔향시간, EDT(sec)와 D50(%)값의 차이를 분석한 결과 배치 방법의 변화에 따른 차이는 크지 않았던 결과로 식재 위치에 따른 소음저감의 차이는 거의 없는 것을 알 수 있었다. 본 연구를 바탕으로 식물을 통한 실내환경 개선이 가능할 것으로 기대됨에 따라 향후 다양한 실내음향 파라메타간의 상호 영향성에 관한 실험 데이터 구축이 필요하며, 세부적인 실험을 위해 식물의 잎모양과 식물높이, 토양의 흡음 등에 대한 연구가 실행되어야 할 것으로 판단된다.