• 분석과학
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• 제18권4호
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• pp.344-354
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• 2005

최근 들어 실내공기질 악화의 주 오염원인 건축자재에 대한 관심이 고조되면서 건축자재 오염물질 방출시험 자료 구축이 중요하게 됨에 따라, 신뢰성 있는 자료 확보를 위해 건축자재 방출시험 정도 관리에 대한 필요성이 대두되었다. 이에 본 연구는 건축자재 방출시험 성능에 대한 정도관리를 위해 총 휘발성 유기화합물과 포름알데히드에 대하여 기기분석 재현성, 회수율, 검출한계, 중복 및 반복채취 재현성, 파과용량 평가 등을 실시하였다. 기기분석 및 시료채취에 대한 재현성은 20~30% 이내의 양호한 결과를 보였으며, 회수율은 80% 이상으로 나타났으며, 파과 역시 일어나지 않아 소형챔버법에 의한 성능은 전반적으로 만족할 만한 수준을 보였다. 따라서, 소형챔버를 이용한 건축자재 오염물질 방출시험방법은 신뢰성있는 자료를 제공해 줄 수 있을 것으로 판단된다.

• 한국환경보건학회지
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• 제33권4호
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• pp.255-263
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• 2007

Indoor air quality is the dominant contributor to total personal exposure because most people spend a majority of their time indoors. The purposes of this study were to evaluate the alternative method for improvement of indoor air quality in house after coating titanium dioxide ($TiO_2$) photocatalyst for interior part of the house using nitrogen dioxide ($NO_2$) multiple measurements. To evaluate the alternative method in indoor environment, daily indoor and outdoor $NO_2$ concentrations of an apartment and a detached house were daily measured for consecutive 21 days in winter and summer, respectively, Another daily 21 measurements were carried out after $TiO_2$ coating on wall paper of interior part in houses. All $NO_2$ concentrations were measured by passive filter badges. Indoor air quality models using mass balance are useful tool to quantify the relationship between indoor air pollution levels, ambient concentrations, and explanatory variables. Using a mass balance model and linear regression analysis, penetration factor (ventilation rate divided by sum of ventilation rate and decay rate) and source strength factor (emission rate divided by sum of ventilation rate and decay rate) were calculated. Subsequently, the decay constants were estimated. In this study. magnitude of improvement of indoor air quality could be evaluated by decay constant.

• 한국물환경학회지
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• 제27권4호
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• pp.445-460
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• 2011

The objective of this study was to construct and assess the applicability of the EFDC model for Saemangeum Reservoir as a 3D hydrodynamic and water quality modeling tool that is necessary for the effective management of water quality and establishment of conservation measures. The model grids for both reservoir system only and reservoir-ocean system were created using the most recent survey data to compare the effects of different downstream boundary conditions. The model was applied for the simulations of temperature, salinity, water quality variables including chemical oxygen demand (COD), chlorophyll-a (Chl-a), phosphorus and nitrogen species and algal biomass, and validated using the field data obtained in 2008. Although the model reasonably represented the temporal and spatial variations of the state variables in the reservoir with limited boundary forcing data, the salinity level was underestimated in the middle and upstream of the reservoir when the flow data were used at downstream boundaries; Sinsi and Garyuk Gates. In turn, the error caused to increase the bias of water quality simulations, and inaccurate simulation of density flow regime of river inflow during flood events. It is likely because of the loss of momentum of sea water intrusion at downstream boundaries. In contrast to flow boundary conditions, the mixing between sea water and freshwater was well reproduced when open water boundary condition was applied. Thus, it is required to improve the downstream boundary conditions that can accommodate the real operations of the sluice gates.

• 한국환경과학회지
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• 제8권2호
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• pp.155-160
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• 1999

To investigate the water quality characteristics and eutrophication of the Keum River, survey were conducted on samples collected from 6 stations in Aug. and Oct. in 1995 and Jan. and May in 1996. The results were summarized as follows ; Concentration of pollutants were in the range of 1.74~6.35(mean 3.81)mg/$\ell$for BOD and 1.98~8.21(5.14)mg/$\ell$for COD and 1.46~51.94(18.52)g/$\ell$for TSS. Water quality were evaluate to be 2~3 grade of station 1 and other stations were 3~4 grade of water quality criteria. The concentration of nutrients were in the range of 55.2~735.3(309.3)$\mu\textrm{g}$-at/$\ell$for Dissolved inorganic nitrogen(DIN) and 0.06~6.03(2.80)$\mu\textrm{g}$-at/$\ell$ for dissolved inorganic phosphate(DIP). Nutrient concentrations in Keum River were usually high and the DIN/DIP ratio ranged from 72 to 2648. The concentration of chlorophyll-a was in the range of 1.1~143.7(44.3)mg/㎥. Chlorophyll-a concentration were high 10mg/㎥ except station 1, which is the value of eutrophication criteria by EPA. Correlations between nutrients and chlorophlly-a were not significant. According to eutrophication evaluation, Keum river was equivalent to the eutrophic state.

• International Journal of Reliability and Applications
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• 제11권1호
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• pp.55-67
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• 2010

There has been a recent upsurge in demand for the improvement of car reliability in the Northern American which is the primary market of South Korea automobile industry. It has been required that the warranty for transmission control unit for passenger cars directly related to passenger safety or security should be extended for 10 years and 160,000 km. In this paper, the test method for reliability and evaluation criteria is presented to evaluate the reliability on the automatic transmission controller. Reliability certification test can be roughly divided into two types: a quality test and life assessment test and a quality test can be subdivided into a basic performance test and environmental resistance test. There are 3 types of tests on the performance test for automatic transmission controller and environmental resistance test is composed of 14 items. Life test is performed with only the product passed this quality test. In this study, operation limit test at the high-temperatures, accelerated life test under specific temperature and accelerated life test for 2 or 3 stress levels are shown as a way for life test.

• 한국환경복원기술학회지
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• 제21권5호
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• pp.39-60
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• 2018

National parks are designated for the purpose of maintenance, conservation and utilization of different habitats. Therefore, it is necessary to select habitats of a high value as a protected area in order to balance conservation and development. However, the existing national park boundary adjustment and new designation criteria only focused on the endangered species and protected area, without proper evaluation of the habitat value of actual species. Therefore, this study aims to quantitatively evaluate habitat function in terms of biodiversity and habitat value, so that it can be referred to for the designation and boundary adjustment of national parks. We assessed species diversity and habitat values for each of the habitat types, for mammals only, as they are able to choose preferred habitats. In order to evaluate biodiversity, we used Maxent to derive species richness map and used InVEST's Habitat quality model to evaluate habitat value. As a result of evaluation, species richness was high in the national park boundary area. Also, even if the same edge is adjacent to the development area depending on the land cover, the species richness is low. Compared with Wolaksan and Sobaeksan National Park, the species richness and habitat value of the northern area, which is connected with other forests, were higher than those of the southern area where roads were developed. Therefore, it is expected that the use of the result of this study for the national park boundary adjustment and management will enhance the function of the national park as a habitat.

• 한국습지학회지
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• 제18권3호
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• pp.218-225
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• 2016

수변지역은 하천의 수질 및 수생태계의 보전과 수변경관의 훼손 방지 특히, 안정적인 상수원의 확보를 위하여 다양한 정책과 계획이 수립되어 왔다. 그럼에도 불구하고 상수원보호구역과 수변구역 등 특정지역을 제외한 수변지역은 소규모 개발사업이 무분별하게 입지하게 되면서 하천의 수질 및 경관을 훼손되고 있다. 본 연구에서는 사업유형별로 동 식물, 지형 지질, 경관, 수질 등의 측면에서 예상되는 환경영향을 분석하고, 환경적 영향 정도에 따라 3-12점까지의 환경점수를 부여하여 중점검토사업과 일반검토사업, 간이검토사업 등으로 구분하였다. 마지막으로 사업유형별로 예상되는 환경영향을 회피하거나 최소화할 수 있도록 평가항목별로 평가기준을 마련하여, 수변지역의 소규모 개발사업을 합리적으로 규제하여 친환경적 개발이 이루어질 수 있도록 하였다.

• 한국물환경학회지
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• 제23권5호
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• pp.591-599
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• 2007

The quality of water released from a stratified reservoir is dependent on various factors such as the location and shape of intake facility, structure of reservoir stratification, profile of water quality constituent, and withdrawal flux. Sometimes, selective withdrawal capabilities can provide the operational flexibility to meet the water quality demands both in-reservoir and downstream. The objective of this study was to evaluate the performance of a one-dimensional reservoir selective withdrawal model (SELECT) as a tool for supporting downstream water quality management for Daecheong and Imha reservoirs. The simulated water quality variables including water temperature, dissolved oxygen (DO), conductivity, turbidity were compared with the field data measured in tailwater. The model showed fairly satisfactory results and high reliability in simulating observations. The coefficients of determinant between simulated and observed turbidity values were 0.93 and 0.95 for Daecheong and Imha reservoirs, respectively. The outflow water quality was significantly influenced by water intake level under fully stratified condition, while the effect of intake amount was minor. In conclusion, the SELECT is simple but effective tool for supporting downstream water quality prediction and management for both reservoirs.

• 한국물환경학회지
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• 제29권5호
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• pp.630-640
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• 2013

It is one of the most critical steps identifying impaired waterbodies exactly in the selection of target water quality indicators for the management of Total Maximum Daily Loads (TMDLs). Excess ratio and excess level were applied and analyzed by the stream zone basis in order to evaluate water impairment for Nakdong, Geum, Youngsan and Seomjin rivers. Each river basin was divided into stream zones in the light of its watershed and waterbody characteristics. Selected water quality parameters discussed in this study were pH, DO, BOD, COD, SS, T-P, T-Coli and F-Coli. The excess ratios of the water quality parameters were used to discriminate water bodies that did not meet water quality standards. The excess levels were used to classify the degradation of water quality. The excess ratios and the excess levels to the water quality criteria of the medium influence areas were used for each stream zone. The results indicate that the excess ratios and the excess levels are varied on the stream zone in each river basin. Three parameters, pH, DO and SS, met water quality standards in all stream zones. The other five parameters indicated very high excess ratios in most waterbodies, and especially T-P and T-Coli revealed to be very high excess levels in some waterbodies. These parameters could be considered as major target indicators for the management of TMDLs.

• 한국환경과학회지
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• 제7권5호
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• pp.591-598
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• 1998

This study was conducted to evaluate water quality in the Keum River estuary using principal component analysis. The results was summarized as follow; Water quality in the Keum River estuary could be explained up to 70.40% by three factors which were included in the inffluent loading by the Keum River and Kyungpo cheon(38.99%), seasonal variation and organic matter pollution(19.05%), sediment resuspension and internal metabolism(12.35%). For spatial variation of factor score, artificial pollutant loading is highest at st.1, below Keum River barrage, and decreases toward the outer sea. For annual variation of factor score, factor 1 was highly related to artificial pollutant leading, and it was gently increased in 1994. Also, organic matter pollution, sediment resuspension and internal metabolism were increased to every year. It is necessary to control the nutrient leading by Keum river and Kyongpo cheon for Water quality management of estuary.