• 한국환경과학회지
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• 제22권12호
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• pp.1683-1690
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• 2013

We investigated the spatial and temporal variations of phytoplankton in Youngil Bay as well as the effect of water physico-chemical parameters. Water samples at three stations were collected and measured monthly from May to November in 2010. The taxa of phytoplankton observed in this study were classified as 33 Bacillariophyceae, 23 Dinophyceae, 1 Euglenophyceae, 2 Crysophyceae and 1 Cryptophyceae. The highest biomass of phytoplankton was observed at inner station in September, which was characterized high concentration of dissolved inorganic phosphate(DIP) in surface water after rainfall. Nutrient concentrations, chlorophyll-a and phytoplankton biomass values showed the marked trend to decrease from the inner bay to the outer bay. Pearson's correlation co-efficient between salinity and other water parameters including chlorophyll-a, pH and DIP showed the strong negative relationship r=-0.82, r=-0.78 and r=-0.75 (p<0.01), respectively. These results indicate that the water quality of Youngil Bay could be stimulated by nutrient enriched input from Hyeogsan River discharge, and the spatial and temporal distribution of phytoplankton biomass principally limited to DIP concentration from Hyeogsan river.

• 한국산학기술학회논문지
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• 제15권8호
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• pp.4901-4907
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• 2014

본 연구는 대학기숙사의 전반적인 시설수준이 거주 학생들의 학업성취도에 미치는 영향을 분석하였다. 이를 통하여 기숙사 특성화를 통한 지방대학의 기숙사운영에 관한 시사점을 제공하고, 나아가 인구구조 변화와 학령인구 감소에 따른 지방대학의 발전방향에 관한 가이드라인을 제시하고자 한다. 본 연구에서는 이를 위해 충청북도에 소재한 S대학의 기숙사 사례를 분석하여 다음과 같은 연구결과를 도출하였다. 먼저 대학기숙사의 전반적인 시설수준이 양호할수록 거주학생들의 학업성취도가 높은 것으로 나타났다. 다음으로 대학기숙사의 개별실 공간특성에 따라 거주학생들의 학업성취도가 영향을 받음을 알 수 있었다. 특히 공동으로 생활하는 학생의 수가 많을수록 학업성취도가 낮아지는 현상을 발견할 수 있었다. 이러한 분석결과는 향후 학령인구 감소에 따라 기숙사 재원인원이 감소하게 되는 경우에는 다인실을 1인실 또는 2인실로 개조할 수 있는 가변형평면의 개발과 적용이 중요하다는 점으로 인식되어 진다.

• Environmental Engineering Research
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• 제19권4호
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• pp.331-338
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• 2014

Descriptive statistics methods were used to study the spatiotemporal variations and sources of ambient particulate matter ($PM_{10}$) in Luzhou, China. The analyzed datasets were collected from four national air quality monitoring stations: Jiushi (S1), Xiaoshi (S2), Zhongshan (S3), Lantian (S4) over the period of 2003-2012. This city was subjected serious $PM_{10}$ pollution, and the long-term annual average $PM_{10}$ concentrations varied from 76 to $136{\mu}g/m^3$. The maximum concentration was more than 3-fold of the annual average ($40{\mu}g/m^3$) issued by EPA-China for the ambient air quality. General temporal pattern was characterized by high concentrations in winter and low concentrations in summer, and general spatial gradient was in the reduction order of S2 > S4 > S3 > S1, which were both due to different particulate contributors and special meteorological conditions. The source apportionment indicated that vehicular emissions, road dusts, coal burning and chemical dusts were the major contributors of the identified $PM_{10}$ pollution, and the vehicular emissions and the road wear re-suspended particles dominated the heavy $PM_{10}$ pollution in recent years. Two other potential sources, agricultural and celebration activities could decrease the air quality in a short term. Finally, some corresponding suggestions and measures were provided to improve the air quality.

• 한국물환경학회지
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• 제37권6호
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• pp.458-468
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• 2021

In this study, we investigated the variations of dissolved organic matter (DOM) in an agricultural reservoir during the monsoon period (June to October, 2020) with respect to the organic carbon concentration (DOC), molecular weight distribution, and optical properties. The monsoon period was divided into three phases - beginning storm (BS), during storm (DS), and after storm (AS). Our results showed significant differences in the concentrations and characteristics of DOM during the summer monsoon. The DOC concentrations were decreased after the monsoon, probably due to a dilution effect. In contrast, increasing trends were observed in the specific UV absorbance (SUVA), and relative abundances of humic-like fluorescence and larger-sized compounds. These observations implied that the large-sized and humic-like organic components with terrestrial origins strongly affected the reservoir DOM after the summer monsoon. Meanwhile, biopolymer size fraction, which is associated with algal activity, became more abundant after the monsoon. These results suggest that DOM with autochthonous sources became dominant as a result of the inflow of nutrients into the reservoir after the storm. Spatial changes in DOM within the reservoir were not pronounced as much as the temporal variations. All taken, it can be concluded that the summer monsoon simply led to the decrease of DOM concentrations while the sources and the quality of DOM underwent substantial changes, which may enrich refractory organic matter in the reservoir. This study reveals the importance of in-depth DOM quality monitoring before and after summer monsoon for effective water quality management in agricultural reservoirs.

• 한국환경과학회지
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• 제20권12호
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• pp.1647-1661
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• 2011

The Government had devised legislation of Special Act and drew up guidelines for improving air quality in Seoul Metropolitan area. In 2007 local government of Seoul, Incheon and Gyeonggi conducted the results of application policy by reduced air pollutants emission for the first time. Although there was reduction of air pollutant emission in each local government, it was ineffective as expected using air pollution monitoring database. Therefore we worked out a way to prepare modeling input data using the results of enforcement plan. And we simulated surface $NO_2$ and PM10 before and after decrease in air pollutants emission and examine reduction effects of air pollution according to enforcement regulation except other influence, by using MM5-SMOKE-CMAQ system. Each local government calculated the amount of emission reduction under application policy, and we developed to prepare input data so as to apply to SMOKE system using emission reduction of enforcement plan. Distribution factor of emission reduction were classified into detailed source and fuel codes using code mapping method in order to allocate the decreased emission. The code mapping method also included a way to allocate spatial distribution by CAPSS distribution. According to predicted result using the reduction of NOx emission, $NO_2$ concentration was decreased from 19.1 ppb to 18.0 ppb in Seoul. In Gyeonggi and Incheon $NO^2$ concentrations were down to 0.65 ppb and 0.68 ppb after application of enforcement plan. PM10 concentration was reduced from 18.2 ${\mu}g/m^3$ to 17.5 ${\mu}g/m^3$ in Seoul. In Gyeonggi PM10 concentration was down to 0.51 ${\mu}g/m^3$ and in Incheon PM10 concentration was decreased about 0.47 ${\mu}g/m^3$ which was the lower concentration than any other cities.

• 한국BIM학회 논문집
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• 제9권1호
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• pp.32-41
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• 2019

As population in Sarasota and Manatee Counties, Florida in the United States is projected to increase, land use changes from land development happen continuously. The more land development means the more impervious surfaces and stormwater runoff to Sarasota Bay, which causes critical impact on the resiliency of the ecosystem. In order to decrease its impact on water quality and the ecosystem function of Sarasota Bay, it is important to assess the resilient status of communities that create negative impacts on the ecosystem. Three types of guiding principles of resiliency for Sarasota Bay watershed are suggested. To assess resiliency status, three indexes - vulnerability index, socio-economic index, and ecological index are developed and analyzed by using geographic information system for each census tract in the two counties. Since each indicator for vulnerability index, socio-economic index, and ecological index is measured with different metrics, statistical standardizing method - distance from the best and worst performers is used for this study to directly compare and combine them all to show total resilience score for each census tract. Also, the ten most and the ten least scores for the total resilience index scores are spatially distributed for better understanding which census tracts are most or least resilient. As Sarasota Watershed boundary is also overlaid, it is easy to understand how each census tract attains its resilience and how each census tract impacts to Sarasota Bay ecosystem. Based on results of the resiliency assessment several recommendations, guidelines, or policies for attaining or enhancing resiliency are suggested.

• 농촌계획
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• 제29권3호
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• pp.91-97
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• 2023

The purpose of this research is to apply the regional development attractiveness of the national level determined in the previous study to the city and county level of Chungcheongnam-do. We verified results with the population change of the floating population data. In order to measure regional development attractiveness in 2020, Chungcheongnam-do's integrated air environment index and per capita gross regional product were gathered. Population movement data over the past five years have been used to analyze population changes in the floating population data. Regional development attractiveness depended on the data of GDP per capita, which had a large difference between the maximum and minimum values. The rate of increase or decrease in population change by city and county in Chungcheongnam-do over the past five years has changed significantly since 2021 and characteristics of each group were grouped into four groups. Based on the environment and economic feasibility of the region, it can be the starting point for a new analysis of Korea's regional development projects and the selection of target sites. Policy suggestions can also be made in spatial plans such as short-term comprehensive plans, long-term comprehensive plans, and development plans. It can be a limit of this research that regional development attractiveness was determined by the relatively large per capita gross domestic product. It is necessary to further develop regional development attractiveness by closely investigating the characteristics of the region, social problems, and emissions of environmentally harmful substances.

• 대한방사선치료학회지
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• 제25권2호
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• pp.175-180
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• 2013

목 적: 방사선치료에 있어 환자자세 설정(Set-up) 오차를 줄이기 위하여 많은 장비들이 개발되어 왔다. CBCT 촬영은 Set-up 오차를 줄이고, 정확한 치료를 수행하는 최신 방법 중 하나이다. CBCT의 조사야를 조절하여 영상의질(Image quality) 향상과 피폭선량을 측정하고 분석함으로써 임상에서 최적화하여 사용할 수 있는 치료조사야(Field size)를 제시하고자 한다. 대상 및 방법: Catphan phantom을 이용하여 Half fan, Full fan mode로 조사야를 2~16 cm까지 2 cm 간격으로 촬영하였다. Small field size (2 cm, 4 cm), Medium field size (8 cm, 10 cm), Large field size (14 cm 이상)으로 구분하여 Image quality를 평가하였다. CTDi는 CTDi phantom과 Ion chamber를 이용하여 측정 및 분석하였다. 결 과: CT값 일치도(CT number linearity)는 Small, Large field size에서 촬영한 값이 Medium field size보다 크게 나타났다. 공간분해능(Spatial resolution)은 Full fan에서 Small field size촬영을 제외하고 나머지 Field size에서 크게 차이가 나지 않았다. Half fan에서는 많은 차이를 보였다. CT 값 균일도(HU uniformity)는 Full fan에서는 Medium size를 제외하고는 제조사에서 권고하는 값을 초과하였으며, Half fan에서는 모든 Field size가 Full fan에서는 Medium field size에서는 안정된 값으로 분석되었다. CT 피폭선량(CTDi)는 Medium field size에서 증가 할수록 루트함수의 그래프의 형태로 나타났다. 결 론:Small field size에서는 Image quality와 실용성의 측면에서도 적절하지 않은 것으로 사료된다. Medium field size는 Large field size에서 보다 Image quality도 우수하고 환자의 피폭선량을 줄일 수 있으므로 본 논문에서는 CBCT 촬영 시 Field size 8~10 cm 촬영이 유용하다고 사료된다.

• 생태와환경
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• 제35권1호통권97호
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• pp.36-44
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• 2002

본 연구는 1993년부터 2000년까지 소양호의 총인, 총질소, 전기전도도, 엽록소의 시${\cdot}$공간적 경향을 통계기법을 적용하여 파악하였다. 호수내의 수질특성은 연간강우량 및 수계의 유입량에 의해 변동되었으나, 변동 정도는 조사지역에 따라 역동적인 차이를 보였다. 맨-켄달검정법 (Mann-Kendall test)으로 연별 수질변화를 분석한 　결과,　전기전도도, 총인, 엽록소-a는 8년 동안 모든 지점에서 증가 및 감소 경향이 없으나 TN은 극히 미약하게 감소하는 경향을 보였다. 총인은 유입량 및 강우에 의해 결정되는 것으로 밝혀졌다. 공간적 분석결과에 따르면, 전기전도도는 호수내 상류에서 하류로 감소하는 경향을 보였고 장마중 상류에서는 집중 강우동안 최소값을 보이고 하류에서는 수체류　현상으로 10월에 최소값을 나타냈다. 총인 및 총질소는 장마중에 최대값을 나타내면서 전기전도_도의 변화 양상과 역관계를 나타냈다. 호수내 1차 생산력의 척도로서 측정된 엽록소-a의 농도는 영양염류의 농도 및 계절에 따라 큰 차이를 보였다. 계절별 총인에 대한 엽록소 농도의 회귀 분석결과에 따르면, 장마 전 및 장마 중에는 $R^2$값이 0.003이하이지만 장마후 $R^2$값은 0.82로서 조류생장이 인의 농도에 의해 결정되는 것을 확인하였다. 반면 질소의 농도는 계절에 상관없이 엽록소의 농도와 극히 미약한 관계를 보였다.

• 한국방사선학회논문지
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• 제17권5호
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• pp.671-677
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• 2023

미세 섬광 픽셀을 사용하여 섬광체 블록을 구성할 경우 섬광체 블록 가장 자리에 위치한 섬광 픽셀들에서 중첩되어 영상화되는 결과가 나타난다. 이를 해결하기 위해서 섬광체 블록과 광센서 사이에 광가이드를 삽입하여 모든 섬광 픽셀들의 영상을 분리하여 획득하였다. 그러나 광가이드를 통해 빛의 손실이 발생할 수 있으며, 이는 에너지 분해능의 감소로 결국 영상의 질에 영향을 미치게 된다. 이에 본 연구에서는 광가이드의 옆면에 반사체를 사용하여 더욱 우수한 섬광 픽셀의 분리가 가능하며, 빛 손실을 최소화해 우수한 에너지 분해능을 확보할 수 있는 검출기를 설계하였다. 이전 연구와 비교 평가를 위해 빛 시뮬레이션이 가능한 DETECT2000을 통해 평면 영상을 획득하여, 분리 정도 및 빛 수집율을 평가하였다. 광가이드의 옆면에 반사체를 사용할 경우, 광가이드의 물질에 상관없이 모든 물질에서 매우 우수한 분리 정도를 나타내었으며, 이는 이전 연구에 비해 더욱 우수한 분리 결과를 나타내었다. 또한 빛 수집율은 반사체 적용하였을 경우, 그렇지 않은 경우에 비해 5배 이상 우수한 수집율을 보였다. 본 검출기를 소동물용 양정자방출단층 촬영기기에 적용할 경우 우수한 공간분해능 및 에너지 분해능을 통해 우수한 영상의 질을 확보할 수 있을 것이다.