• Journal of Korean Society of Environmental Engineers
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• v.22 no.11
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• pp.2025-2036
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• 2000

A physicochemical process called ultra rapid coagulation(URC) was applied as a pilot scale to recover eutrophicated lake water at Inkyung Lake located on-campus in Inha university. The URC was uniquely designed to completely remove the presence of phosphorus up to 95%, which in turn leading to lessen the level of eutrophication of lake. For a pilot test of period, the lake was restored showing Carlson's Trophic State Index(TSI) of mesotrophic state which accounts for the reduction of total phosphorus and chlorophyll-a down to approximately 55 from 70 and 73, respectively. A residual presence of aluminum and additional coagulants in the effluent was tested for their potential effects on Photobacterium phosphoreum. The effect concentration ($EC_{50}$-15 min) observed in the effluent revealed that the bioactivity of Photobacterium phosphoreum was not influenced by the residual presence of coagulants. After the pilot test of period, the lake was consequently restored as a mesotrophic state in obtaining the second grade of lake water quality. The URC may be further applied for restoration of greater scale of lake in eutrophication.

• Journal of the Korean Society for Marine Environment & Energy
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• v.18 no.4
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• pp.245-253
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• 2015

Total acid digestion and 1 M HCl extraction methods were used to investigate the pollution status and the degree of ecological risk of trace metals in surface sediments from the Ulsan-Onsan coast. Total concentrations of trace metals (Cu, Cd, Pb, Zn, and Hg) were two-fold higher in surface sediments from Onsan coast than in those from Ulsan coast. The mean labile fractions of the total concentrations of Cd and Pb were 72% and 78%, respectively, indicating a high contribution from anthropogenic sources, whereas Cr, Li, Ni, and As in the residual fraction exceeded 80%, indicating a high contribution from natural sources. According to the results of assessment of trace metal pollution using the sediment quality guidelines in Korea, the concentrations of Cu, Pb, Zn, and Hg were higher than the values of the probable effects level (PEL) at some stations of Onsan coast, and the concentrations of Cr and Ni were lower than the values of the threshold effects level (TEL). The pollution level and ecological risk of the trace metals were analyzed using various indexes (EF, $I_{geo}$, m-PEL-Q, and ERI). Our results showed that the degree of pollution by trace metals (Cu, Cd, Pb, Zn, and Hg) on the Ulsan-Onsan coast was high, and Hg and Cd were the major potential ecological risk factors.

• Journal of the Korean GEO-environmental Society
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• v.25 no.11
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• pp.33-43
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• 2024

In this study, data from the Gwangyang Automated Synoptic Observing System (ASOS) meteorological observatory were utilized for drought assessment. Drought occurrence days were evaluated using the Precipitation-based Standardized Precipitation Index (SPI) and two types of Standardized Precipitation Evapotranspiration Index (SPEI) (SPEI_Thornthwaite and SPEI_Penman-Monteith), considering precipitation and evapotranspiration. The SPI and SPEIs yielded generally similar quantitative results for drought occurrence days. However, the SPEI_Penman-Monteith, which uses the physically-based Penman-Monteith method for evapotranspiration estimation, showed a higher number of drought days compared to the SPI_Thornthwaite. The amount of evapotranspiration by the Penman-Monteith method had high seasonal variability and high moisture loss, while the amount of evapotranspiration by the Thornthwaite method had low variability and low moisture loss. Consequently, the SPEI_Thornthwaite had a higher correlation with the SPI compared to the SPEI_Penman-Monteith. Since the SPEI_Penman-Monteith index can more accurately calculate the amount of water loss caused by the hydrological circulation, more reasonable results are derived in calculating the number of drought occurrence days. However, due to the lack of sufficient high-quality meteorological data at ASOS observatories, the Penman-Monteith method may be difficult to apply. In such cases, the SPEI_Thornthwaite, estimating evapotranspiration based solely on monthly average temperature, can be used as an alternative.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.4
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• pp.338-344
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• 2021

Elements that threaten domestic security, such as diplomatic changes in the four major powers surrounding the Korean Peninsula and restrictions on supply and demand of parts due to COVID-19, are constantly increasing. The importance of localizing weapon systems has grown to respond proactively to the threat. As localization is not conducted evenly by the field, it is necessary to change the criteria for selecting localization targets. Establishing standards for selecting targets is difficult due to a lack of research to identify targets. This paper emphasized that the smooth supply of parts from overseas should be examined to identify targets for localization. If suppliers are not distributed evenly in the market, there is a risk of potential supply problems. CRk and HHI, representing the market structure, were proposed as indicators for evaluating the degree of smoothness quantitatively. Among them, CRk is used in Korea to check the market concentration, but there is a limit in the subjectivity of the evaluator, so it cannot be applied without a separate study on the market structure. Therefore, HHI should be applied.

• Survey Research
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• v.10 no.2
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• pp.45-69
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• 2009

This paper explores how multiple facets of social capital in Korea affects social conflict. The notion of social capital is composed of several elements including (1) social trust in generalized others (2) confidence in public sector fairness and the principles of democracy (3) social networks and closures and (4) community spirit and collective norms. We particularly examine how these multiple dimensions of social capital affect an individual`s tendency of social conflict orientation. The findings address the following four points. First, an individual, who trusts generalized others in a society, is less likely to be exclusive and conflict-oriented. Second, the more an individual has confidence in the efficacy of democratic processes and public sector fairness, the more (s)he is likely to be social integration oriented. When an individual, in contrast, gives strong support to a particular party (or government in power), the person is more likely to be conflict oriented. Third, an individual who mobilizes exclusive social closures to solve a problem is more likely to be conflict oriented. However, an individual who maintains a variety of inclusive social networks is more likely to be social integration oriented. Finally, the internalization of collective norms does not affect directly the tendency of individual's social conflict orientation. Increasing social capital at the individual level does not automatically guarantee societal level conflict resolutions. Rather, building extensive social closures based on strong family or hometown ties, school connections, political interests has detrimental effects on social integration and conflict resolutions. More, constructive social integration in a society requires higher level of open social networks, consistent administrative and democratic procedures, and social trust in generalized others.

• Korean Journal of Ecology and Environment
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• v.53 no.1
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• pp.31-45
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• 2020

The biological indices based on the community structure with species richness and/or abundance are commonly used to assess aquatic ecosystem health. Meanwhile, recently functional traits-based approach is considered in ecosystem health assessment to reflect ecosystem functioning. In this study, we developed a database of biological traits for 136 taxa consisting of major stream insects (Ephemeroptera, Plecoptera, Trichoptera, Coleoptera, and Odonata) collected at Korean streams on the nationwide scale. In addition, we obtained environmental variables in five categories (geography, climate, land use, hydrology and physicochemistry) measured at each sampling site. We evaluated the relationships between community indices based on taxonomic diversity and functional diversity estimated from biological traits. We classified sampling sites based on similarities of their environmental variables and evaluated relations between clusters of sampling sites and diversity indices and biological traits. Our results showed that functional diversity was highly correlated with Shannon diversity index and species richness. The six clusters of sampling sites defined by a hierarchical cluster analysis reflected differences of their environmental variables. Samples in cluster 1 were mostly from high altitude areas, whereas samples in cluster 6 were from lowland areas. Non-metric multidimensional scaling (NMDS) displayed similar patterns with cluster analysis and presented variation of taxonomic diversity and functional diversity. Based on NMDS and community-weighted mean trait value matrix, species in clusters 1-3 displayed the resistance strategy in the life history strategy to the environmental variables whereas species in clusters 4-6 presented the resilience strategy. These results suggest that functional diversity can complement the biological monitoring assessment based on taxonomic diversity and can be used as biological monitoring assessment tool reflecting changes of ecosystem functioning responding to environmental changes.

• Sleep Medicine and Psychophysiology
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• v.21 no.1
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• pp.5-13
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• 2014

Objectives: Depression, sleep complaints and cognitive impairments are commonly observed in the elderly. Elderly subjects with depressive symptoms have been found to show both poor cognitive performances and sleep disturbances. However, the relationship between sleep complaints and cognitive dysfunction in elderly depression is not clear. The aim of this study is to identify the association between sleep disturbances and cognitive decline in late-life depression. Methods: A total of 282 elderly people who underwent nocturnal polysomnography in a sleep laboratory were enrolled in the study. The Korean version of the Neuropsychological Assessment Battery developed by the Consortium to Establish a Registry for Alzheimer's Disease (CERAD-K) was applied to evaluate cognitive function. Depressive symptoms were assessed with the geriatric depression scale (GDS) and subjective sleep quality was measured using the Pittsburg sleep quality index (PSQI). Results: The control group ($GDS{\leq}9$) when compared with mild ($10{\leq}GDS{\leq}16$) and severe ($17{\leq}GDS$) depression groups, had significantly different scores in the Trail making test part B (TMT-B), Benton visual retention test part A (BVRT-A), and Stroop color and word test (SCWT)(all tests p<0.05). The PSQI score, REM sleep duration, apnea-hypopnea index and oxygen desaturation index were significantly different across the three groups (all indices, p<0.05). A stepwise multiple regression model showed that educational level, age and GDS score were predictive for both TMT-B time (adjusted $R^2$=35.6%, p<0.001) and BVRT-A score (adjusted $R^2$=28.3%, p<0.001). SCWT score was predicted by educational level, age, apnea-hypopnea index (AHI) and GDS score (adjusted $R^2$=20.6%, p<0.001). Poor sleep quality and sleep structure alterations observed in depression did not have any significant effects on cognitive deterioration. Conclusion: Older adults with depressive symptoms showed mild sleep alterations and poor cognitive performances. However, we found no association between sleep disturbances (except sleep apnea) and cognitive difficulties in elderly subjects with depressive symptoms. It is possible that the impact of sleep disruptions on cognitive abilities was hindered by the confounding effect of age, education and depressive symptoms.

• Proceedings of the Korean Statistical Society Conference
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• 2000.11a
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• pp.207-212
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• 2000

본 연구는 최근의 사회조사와 선거자료를 이용하여 한국사회의 지역주의의 특징을 살펴보고자 한다. 첫째, 최근의 선거결과에 보이는 지역주의적 투표는 지역간 사회적 거리를 잘 보여주고 있다. 둘째, 이러한 사회적 거리는 '편견과 차별'의 형태로 다양한 일상생활에서 존재하고 있다. 많은 사람들은 이러한 편견을 믿고 있으며, 편견에 의한 지역적 차별을 경험하고 있다. 특히 이러한 경험은 특정지역(호남)과 관련되어 있다. 셋째, 이러한 정치적 측면(지역주의적 투표)과 사회적 측면(지역간 편견)을 선거제도와 연결하여 살펴봄으로써, 앞으로 한국사회의 정치제도의 변화에 대한 전망을 할 수 있다. 연구의 잠재적인 가정은 선거에 있어서 지역적인 투표가 무조건 '나쁜' 것만은 아니라는 것이다. 한국 정치에서 나타나는 지도자나 이데올로기의 편향은 많은 사람들로 하여금 투표나 선거에서 출신지를 중요한 요소로 삼게 하였다. 이러한 요소는 쉽게 사라지지는 않을 것이며, 앞으로 선거제도의 변화에 중요한 역할을 할 것이다. 이러한 예측은 세 가지 중요한 요소에 근거하고 있다. 첫째, 유권자들의 지역주의에 대한 믿음과 예측은 쉽게 사라지지 않을 것이다. 둘째, 정치지도자들은 지역주의를 선거와 관련한 자신의 이익을 위해서 최대한 이용할 것이다. 셋째, 지역주의에 근거한 유권자들의 성향은 최근 선거와 투표에서 더욱 강화되고 있다. 정치엘리트들이 지역적인 기반을 중심으로 결합하려는 경향이 강해지고 있다. 이러한 경향은 이들 정치엘리트 사이의 내각중심제에 대한 선호도와 지역당의 출현 가능성을 증가시킬 것이다.도 설치행위의 처분성과 관련하여 횡단보도의 설치행위와 같은 일반적인 명령을 항고소송의 대상으로 할 필요성이 존재한다면 이른바 독일에서의 일반처분이라는 개념을 무리하게 받아들여 이를 행정행위의 한 유형으로 한다거나 우리 판례와 같이 "직접적이고 구체적인 법적 효과"를 미치는 명령이라는 명확치 않은 기준에 의하여 처분성을 인정하기보다는 일반적인 명령과 개별적인 행정행위를 구분하고 명령에 대하여도 취소소송의 대상으로 삼도록 하는 보다 명확하고 일관성 있는 논의전개를 제안하였다.수 있었다.로 첨가하여 48시간 배양한 후 암항원 유전자 발현성을 측정한 결과 세포주에 따라 다소 차이는 있으나 대개 0.2 uM농도에서도 유전자 발현이 유도되었으며 1, 5 uM농도에서 매우 강하게 유도되었다. ADC 처리가 페암세포주의 MHC와 B7 발현을 증가시키는가를 알아보기 위해 1 uM 농도의 ADC를 72시간 처치한 후 FACS 분석을 실시한 결과 4개의 페암세포주에서 MHC 및 B7분자의 발현은 유도되지 않았다. 또 ADC농도가 세포성장에 미치는 영향을 알아보기 위하여 ADC를 0.2, 1, 5 uM농도로 96시간 처치 후 세포수를 측정하여 상대성장지수를 알아본 결과 ADC 처치 농도가 증가함에 따라 세포의 성장은 매우 감소하였다. 결론: 폐암세포주에서 ADC처치는 MAGE, GAGE 및 NY-ESO-1과 같은 세포독성 T 림프구 반응을 유도할 수 있는 암항원의 발현을 증가시킬 수 있으며, ADC의 세포독성과 항원 발현 유발시간을 분석할 때 1 uM 농도에서 48시간 처치한 후 ADC가 없는 배지에서

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.264-264
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• 2023

물순환 과정에서의 증발산은 장기적인 관점에서의 수자원 계획 수립 시 중요한 요소이다. 증발산은 기온, 상대습도, 일사량 등 기상학적 인자뿐만 아니라 증발표면, 식생분포 등 다양한 인자의 복합작용에 의해 일어나므로, 유역 단위에서 발생한 실제증발산(Actual evapotranspiration, AET)을 측정하기에는 기술적인 한계가 존재한다. 그러나 증발산 보완관계(Complementary relationship of evapotranspiration, CRE) 가설을 활용하면, 수문요소의 상호작용을 고려한 모델링을 거치지 않고도, 비교적 간단하게 AET를 추정할 수 있다. 본 연구는 증발산 관측자료를 기반으로 유역 단위에서의 CRE를 검증하고자 하며, 플럭스 타워 등 다양한 관측장비가 설치되어 있는 용담댐 시험유역을 대상유역으로 선정하였다. 용담댐 유역 내 산지에 위치한 덕유산 플럭스 타워에서 측정된 증발산을 AET로 보았으며, 유역 인근에 위치한 전주 기상관측소에서 측정되는 팬 증발량(E_pan)을 잠재증발산량(Potential evapotranspiration, PET)으로 보았다. E_pan 계측시, 증발팬의 가열 등 주변환경 변화로 인해 과다하게 추정되는 값을 보완하기 위해 FAO Penman-Monteith 식을 활용해 팬 증발량 보정계수(Coefficient of pan evaporation, k_p)를 산정하여 적용하였다. 습윤증발산량(Wet evapotranspiration, WET)은 대기가 완전히 포화되었을 때 발생하는 증발산량으로, 댐 수표면에서 계측되는 수면증발량을 WET로 보았다. CRE 검증을 위해 AET와 PET를 각각 WET로 나누어 AET+와 PET+로 무차원화하였으며, 습윤지수(Moisture Index, MI)는 AET를 PET로 나누어 산정하였다. CRE 가설은 MI에 따른 AET+와 PET+가 서로 보완관계를 갖는다는 것인데, 용담댐 유역의 관측자료를 활용하여 CRE를 검증한 결과 AET+와 PET+ 간의 비대칭계수(b)가 1.23인 것으로 나타났다. 이 때의 평균제곱오차(MSE)는 0.599, 결정계수(R₂)는 0.631로 나타나 CRE의 b가 적합하게 추정된 것으로 판단된다. 본 연구결과와 같이 검증된 CRE를 통해 증발산 관측지점이 없거나, 조밀하지 않은 유역의 AET를 간접추정할 수 있으며, 이를 활용해 보다 정확한 댐의 장기유출 모의와 용수공급계획 수립에 도움을 줄 수 있을 것으로 기대된다.

• Journal of the korean academy of Pediatric Dentistry
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• v.47 no.4
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• pp.377-388
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• 2020

The aim of this study was to evaluate the association between various predicting tools and Apnea-Hypopnea Index (AHI) to identify children with sleep disordered breathing (SDB). From 5 to 10 years old who came for orthodontic counseling, 61 children, whom had lateral cephalograms, pediatric sleep questionnaire (PSQ) records, and portable sleep monitoring results, were included in this study. A total of 17 measurements (11 distances and 6 angles) were made on lateral cephalograms. The measurements of lateral cephalograms, PSQ scales and portable sleep monitoring results were statistically analyzed. 49 of 61 (80%) patients showed AHI > 1, which suspected to have SDB and their mean AHI was 2.75. In this study, adenoid size (A/N ratio), position of the hyoid bone from mandibular plane, gonial angle, and PSQ scale were related to a higher risk of pediatric SDB. Also, oxygen desaturation index (ODI) and snoring time from sleep monitoring results were statistically significant in children with SDB using Mann-Whitney test (p < 0.05). In conclusion, evaluation of hyoid bone position, adenoidal hypertrophy, gonial angle in lateral cephalogram, and PSQ scale was important to screen out potential SDB, especially in children with frequent snoring.