• 한국음향학회지
• /
• 제42권1호
• /
• pp.42-49
• /
• 2023

열악한 실내 음환경은 재실자에게 부정적인 영향을 미친다. 선행 연구를 통해 실내 음환경이 재실자의 과업성취도나 직무만족도뿐 아니라 그들의 건강과 웰빙에도 영향을 주는 것으로 알려져왔다. 본 연구는 국내 공공건축물에 위치한 개방형 사무실의 실내 음환경을 평가하고, 재실자의 음환경 쾌적성 향상을 위하여 고려할 필요가 있는 사항을 검토하기 위한 목적으로 수행되었다. 국내 공공건축물에 위치한 13개의 개방형 사무실에서 실내 소음 레벨을 측정하였으며, 측정은 월요일부터 금요일까지 5일간 진행되었다. 측정된 실내 소음 레벨은 ISO 및 EU ALDREN 프로젝트가 개방형 사무실을 대상으로 권장하는 수준을 기반으로 평가하였다. 분석 결과, 근무 시간 동안 재실자가 있는 환경에서의 실내 소음 레벨은 대부분 ISO 기준을 충족하는 것으로 나타났다. 재실자가 없는 심야 시간대의 음환경을 평가한 결과, 3개 사무실의 측정 결과값이 ALDREN의 권장 수준을 충족하지 못하는 것으로 나타났다. 아울러 측정이 진행된 현장의 특성이 실내 소음도에 유의미한 영향을 주는 것으로 나타났다. 건물 외피의 정확한 음향 성능을 파악하는 것이 불가능하였으므로 향후 추가 연구를 통해 건물의 성능과 실내 음환경 간 관계를 규명할 필요가 있다.

• 한국환경과학회지
• /
• 제22권1호
• /
• pp.47-57
• /
• 2013

Studies evaluating the health effects of hazardous air pollutants assume that people's exposure to typical pollutant level is the same as specific regional pollutant level. However, depending on social and demographic factors, time-activity pattern of people can vary widely. Since most people live in indoor environments over 88% of the day, evaluating exposure to hazardous air pollutants is hard to characterize. Objective of this study was to estimate the exposure levels of university students of $NO_2$, VOCs(BTEX) and $PM_{10}$ using the scenarios with time-activity pattern and indoor concentrations. Using data from time-use survey of National Statistical Office in 2009, we investigated time-activity pattern of university students and hourly major action. A total of 1,057 university students on weekday and 640 on weekend spent their times at indoor house 13.04 hr(54.32%), other indoors 7.70 hr(32.06%), and transportation 2.36 hr(9.83%). Indoor environments in which university students spent their times were mainly house and school. Air pollutants concentrations of other indoor environments except house and school such as bar, internet cafe and billiard hall were higher than outdoors, indicating that indoor to outdoor ratios were above 1. According to three types of exposure scenarios, exposure to air pollutants could be reduced by going home after school.

• KIEAE Journal
• /
• 제17권1호
• /
• pp.83-89
• /
• 2017

Purpose: Thermal sensation or thermal comfort was randomly used in many studies which focused on combined effects of thermal and acoustic environments on human perception. However, thermal sensation and thermal comfort are not synonyms. Thermal comfort is more complex human perception on thermal environment than thermal sensation. This study aims to investigate effects of noise on thermal sensation and thermal comfort separately, and also to investigate effects of temperature on acoustic sensation and comfort. Method: Combined thermal and acoustic configurations were simulated in an indoor environmental chamber. Twenty four participants were exposed to two types of noise (fan and babble) with two noise levels (45 dBA and 60 dBA) for an hour in each thermal condition of PMV-1.53, 0.03, 1.53, 1.83, respectively. Temperature sensation, temperature preference, thermal comfort, noisiness, loudness, annoyance, acoustic comfort, indoor environmental comfort were evaluated in each combined environmental condition. Result: Noise did not affected thermal sensation, but thermal comfort significantly. Temperature had an effect on acoustic comfort significantly, but no effect on noisiness and loudness in overall data analysis. More explicit interactions between thermal condition and noise perception showed only with the noise level of 60 dBA. Impacts of both thermal comfort and acoustic comfort on the indoor environmental comfort were analyzed. In adverse thermal environments, thermal comfort had more impact than acoustic comfort on indoor environmental comfort, and in neutral thermal environments, acoustic comfort had more important than thermal comfort.

• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 1998년도 하계종합학술대회논문집
• /
• pp.169-172
• /
• 1998

A 3D-ray tracing using triangular ray tubes for predicting propagation in indoor environments is presented. Employed ray tracing scheme needs no reception sphere often suffered from how to assign the correct radius as a touching ray on the receiver. To verify the developed codes path loss for a rectangular corridor has been computed, measured, and compared with those by image methods, all shows good agreement to each other. Discussions are made on the path loss fluctuations along the distance in a rectangular corridor having a conducting knife.

• 한국대기환경학회지
• /
• 제14권4호
• /
• pp.343-360
• /
• 1998

In this study, comprehensive air quality monitoring was undertaken with a variety of objectives to collect data on the levels of various indoor and ambient air quality parameters in the urban areas of Seoul and Taegu. The sampling sites were comprised of six offices, six residences and six restaurants in each city. The ambient air adjacent to the indoor sites was also simultaneously sampled for the same constituents. The sampling was conducted in two phases: summer of 1994 and winter of 1994/95. A range of air quality parameters were measured simultaneously, which include RSP, CO, COB, NOB, a range of VOC, airborne microbials, temperature, and relative humidity. The indoor and ambient levels of the pollutants measured in this study varied widely between the three types of environments studied. Comparison of median values for the three groups revealed that restaurants had higher indoor levels of most pollutants than homes or offices. There was also a clear pattern of the indoor levels of target pollutants being higher than those outdoors, particularly in restaurants. Concentrations of CO and most of the VOC were found to be significantly higher in the commercial districts, indicating the influence of vehicle exhaust emissions. A very wide range of VOC levels was documented in this study. Although median indoorloutdoor ratios indicated a generally increasing level of VOC indoors when compared to those outdoors, no statistically significant differences were found between indoor and outdoor VOC levels in homes and offices, implying the importance of ambient air quality in determining the quality of indoor air for homes and offices in urban areas. In addition, there was a general pattern of increasing concentrations from summer to winter, and similarly from outdoor to indoor air for nearly all target compounds. The seasonal differences in median levels were very clearly seen for fuel combustion related pollutants such as RSP, CO and VOC, this being attributed to the effects of increased fuel consumption during the cold season and to meteorological factors.

• 실내환경 및 냄새 학회지
• /
• 제17권4호
• /
• pp.303-314
• /
• 2018

The urban railway system is a convenient public transportation system, as it carries many people without increasing traffic congestion. However, air quality in urban railway environments is worse than ambient air quality due to the internal location of the source of air pollutants and the isolated space. In this paper, characteristics of particulate matter (PM) pollution in urban railway environments are described from the perspective of diurnal variation, chemical composition and source apportionment of PM. PM concentrations in concourse, platform, passenger cabin, and tunnel are summarized through an analysis of 34 journal articles published in Korea and overseas. This information will be helpful in developing effective policies to reduce PM pollution in urban railway environments.

• Environmental Engineering Research
• /
• 제12권5호
• /
• pp.203-210
• /
• 2007

Since the emissions composition from the household products have potentially been associated with health risks for building occupants, the chemical composition emitted from the products should be surveyed. The current study identified the emission composition for 42 liquid household products, using a purge-and-trap method. This evaluation was done by classifying the household products into five product classes (deodorizers, household cleaners, color removers, pesticides, and polishes). Nineteen compounds were chosen on the basis of selection criteria. The quality control program for purge-and-trap and analytical systems included tests of laboratory blank Tenax traps and blank water samples, and the determination of calibration equation, measurement precision, method detection limit (MDL), and recovery. The number of chemicals varied according to the product categories, ranging from 4 for the product category of bleaches to 12 for the product categories of air fresheners and nail color removers. For all product categories, the emission composition and concentrations varied broadly according to product. It is noteworthy that most household products emit limonene: 19 of 25 cleaning products; 5 of 6 deodorizers; 1 of 3 pesticides; 3 of 3 color removers; and 4 of 5 polishes. It was suggested that the use of household products sold in Korea could elevate the formation of secondary toxic pollutants in indoor environments, by the reaction of limonene with ozone, which entered indoor environments or might be generated by indoor sources such as electronic air cleaning devices and copying machines.

• 지역사회간호학회지
• /
• 제13권1호
• /
• pp.79-88
• /
• 2002

Purpose: The purpose of this study was to identify the indoor environment i.e. house type and age, ventilation method, use of bed & sofa, cockroach, ants, etc. on HDM (House dust mites), especially Der fI allergen. Method: Samples of dust from mattresses, pillows and the floor were collected by using a vacuum cleaner from April. 2000. The amount of Group I allergen(Der. fI) of HDM (house dust mites) were measured by two-site ELISA. Indoor Environmental characteristics were accessed by using questionnaires on 178 house wives living in the Seoul area. Results: The amount of HDM allergen (Der fI) was higher in sofa using house. There were higher concentrations of HDM allergen (Der fI) in sofas made from quilt material than for those that were made from leather. Homes that had pets like dogs living in them had higher concentrations of HDM allergen (Der fI) than without dogs. Conclusion: The photophobic mites thrive in dark. warm and humid environments; Items such as pillows. mattresses, box springs, blankets. carpets. and upholstered furniture should be considered ideal environments for the mite. Therefore, an indoor environmental control program should be carried out to avoid the HDM allergen.

• 한국환경과학회지
• /
• 제7권6호
• /
• pp.745-751
• /
• 1998

The well-mixed room model has been traditionally used to predict the concentrations of contaminants in indoor environments. However, this is inappropriate because the flow fields in many indoor environments distribute contaminants non-uniformly, due to imperfect air mixing. Thus, some means used to describe an imperfectly mixed room are needed. The simplest model that accounts for imperfect air mixing is a two-zone model. Therefore, this study on development of computer program far the two-zone model is carried out to propose techniques of estimating the concentration of contaminants in the room. To do this, an important consideration is to divide a room into two-zone, i.e. the lower and upper zone assuming that the air and contaminants are well mixed within each zone. And between the zones the air recirculation is characterized through the air exchange parameter. By this basic assumption, the equations for the conservation of mass are derived for each zone. These equations are solved by using the computational technique. The language used to develope the program is a VISUAL BASIC. The value of air exchange coefficient($f_12$) is the most difficult to forecast when the concentrations of contaminants in an imperfectly mixed room are estimated by the two-zone model. But, as the value of $f_12$ increases, the air exchange between each zone increases. When the value of $f_12$ is approximately 15, the concentrations in both zone approach each other, and the entire room may be approximately treated as a single well-mixed room. Therefore, this study is available for designing of the ventilation to improve the air quality of indoor environments. Also, the two-zone model produces the theoretical base which may be extended to the theory for the multi-zone model, that will be contributed to estimate the air pollution in large enclosures, such as shopping malls, atria buildings, atria terminals, and covered sports stadia.

• 한국통신학회논문지
• /
• 제40권8호
• /
• pp.1655-1666
• /
• 2015

본 논문에서는 Fingerprint 기법의 Resource로 신호의 세기가 아닌 이미지를 이용해 좌표정보를 포함하는 이미지 기반의 데이터베이스를 구축하고, 사용자로부터 입력되는 이미지와 유사도 비교를 통해 사용자의 위치추정 기법에 대해 제안한다. Fingerprint 기법은 신호 세기뿐만 아니라 환경에 대한 지역적 잡음 정보들까지 모두 추정에 반영하므로 높은 위치 추정 정확도를 제공한다. 이미지의 유사도는 SURF 알고리즘을 통해 데이터베이스와 사용자 입력 이미지의 특징점을 검출하고, 동일한 특징점 간의 매칭을 통해 비교된다. 여기에서 우리는 RANSAC 알고리즘을 함께 사용하여 검출된 특징점의 노이즈 제거를 통해 이미지 유사도 비교의 정확도를 높였다. 제안하는 기법의 검증을 위해 두 건물의 실내와 주변 실외 환경에서 이미지를 획득하여 데이터베이스를 구축하고, 임의의 위치에서 사용자의 위치를 추정하였다. 추정 된 최종 위치는 데이터베이스에 저장 된 이미지가 가지는 좌표가 사용자의 위치와 가장 근접한 좌표로 검출되는지 확인하였으며 RANSAC을 통해 특징점의 노이즈 제거 전과 제거 후에 대한 이미지 유사도 비교의 성능을 분석하였다.