• Proceedings of the Korea Water Resources Association Conference
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• 2017.05a
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• pp.346-346
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• 2017

기후변화에 따른 기상이변의 동시다발적인 발현은 농촌 지역의 홍수 발생 빈도를 증가시키고 있다. 현재의 기후시스템은 과거의 강우빈도를 기준으로 산정한 설계기준을 벗어나는 강우 사상을 빈번하게 발생시키므로 설계변수의 불확실성을 보다 합리적인 방법으로 정량화할 필요가 있다. 본 연구의 목적은 기후변화에 대응하여 확률론을 이용한 농업용 저수지의 홍수 취약성을 산정하는 데 있다. 먼저 홍수 취약성 해석에 필요한 과거와 미래 수문 자료를 수집하고 전처리 과정을 통해 해석에 적합한 자료로 구축하였다. 설계변수의 불확실성을 분석하기 위해 지속시간별 최대강우량, 유입 설계홍수량에 대해 부트스트랩 (bootstrap) 기법을 적용하여 자료를 재추출하였다. 부트스트 랩은 표본집단의 확률분포에 대해 가정을 하지 않고 표본집단의 통계적 특성을 이용하여 모집단의 통계적 추론을 할 수 있는 비모수적인 리샘플링 기법이다. 부트스트랩 추론은 표본집단의 추정치, 편의, 표준오차를 산정하고 신뢰구간을 추정한다. 부트스트랩 추론을 통해 산정하는 신뢰수준을 이용하여 농업용 저수지의 홍수 취약성을 산정하였다. 본 연구는 설계변수에 내재하는 불확실성을 부트스트랩 기법을 이용하여 정량화하고 확률적인 값을 가지는 홍수 취약성으로 산정하여 제시할 수 있다.

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.397-397
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• 2023

기상이변에 따른 국지성 호우 및 태풍내습으로 인해 재해위험지구에서의 인명 및 재산피해가 지속적으로 발생하고 있다. 특히, 한국의 경우 대부분의 강우가 여름철에 단기간으로 집중되어 하천으로 유출량이 집중되므로 하천수위의 급상승 및 급하강을 일으키게 된다. 하천수위의 빠른 변화는 하천 제방의 국부적인 피해를 주거나 내구성을 저하시키는 요인이 된다. 또한 하천 제방의 붕괴는 제내지에 위치한 도시의 홍수 및 인명피해를 야기할 수 있으므로 하천제방의 안정성 평가를 통한 유지관리의 중요성이 대두되고 있다. 본 연구에서는 홍수취약성지수를 개량한 제방홍수취약성지수를 적용하여 기후변화를 고려한 강우적용시 하천 제방의 안정성평가를 진행하였다. 제방홍수취약성지수는 홍수취약성지수의 형식을 차용하여 하천 제방에 알맞은 인자들로 구성하여 개발된 새로운 기법으로 7개의 인자들의 값들을 기반으로 엔트로피 기법을 사용하여 가중치를 산정하여 취약성지수를 산정하는 방법이다. 다양한 강우시나리오를 적용하여 하천 제방들의 제방홍수취약성지수를 분석하였으며 산정된 취약성 지수들을 이용하여 제방의 안정성을 평가하였다. 또한 저수지 제방의 안전성 평가를 위한 방안으로 제방홍수취약성지수를 적용하기 위한 방안을 제시하고자 한다.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.54 no.1
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• pp.36-44
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• 2009

This experiment was conduced to clarify the effects of growth temperature and radiation on grain weight increase and grain nitrogen accumulation in rice. Final grain weight became heavy and grain-filling duration shortened with radiation increase during grain-filling period (GFP). In addition, grain nitrogen accumulated duration during GFP was influenced strongly, but final grain nitrogen content was influenced slightly by accumulated radiation (AR). Accumulated effective temperature (AET) described well variation of grain weight (GW) and grain nitrogen content (GN), but GW and GN showed large variation under different radiation during GFP, when related with AET or AR, indicating that there was a limiting in describing variation of GW and GN by any single factor between AET and AR. However, AET multiplied by AR could describe relatively well the variations of GW and GN regardless of radiation during GFP.

• Journal of Wetlands Research
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• v.21 no.spc
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• pp.107-116
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• 2019

Multi-purpose dams in Korea play a very important role in water management such as supplying water for living, industrial water, and discharging instream flow requirement to maintain the functions of river. However, the vulnerability of dam water supply has been increased due to extreme weather events that are possible linked to climate change. This study attempts to project the future dam inflow of six multi-purpose dams by using dynamically downscaled climate change scenarios with high resolution. It is found that the high flows are remarkably increased under global warming, regardless of basins and climate models. In contrast, the low flows for Soyangang dam, Chungju dam, and Andong dam that dam inflow are originated from Taebaek mountains are significantly decreased. On the other hand, while the low flow of Hapcheon dam is shown to increase, those of Daecheong and Sumjingang dams have little changes. But, the low flows for future period have wide ranges and the minimum value of low flows are decreased for all dams except for Hapcheon dam. Therefore, it is necessary to establish new water management policy that can respond to extreme water shortages considering climate change.

• Proceedings of the Korea Water Resources Association Conference
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• 2016.05a
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• pp.139-139
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• 2016

가능최대홍수량(Probable Maximum Flood, PMF)이란 대규모 수공구조물을 설계하고자 할 때 막대한 경제적 손실 및 인명피해 등을 막기 위해 기준으로 삼는 설계홍수량이며, 통계학적으로는 약 10,000년 빈도에 해당된다. 우리나라의 호우 특성은 방위, 진행방향 및 위에 따른 해석이 매우 복잡하여 강우를 정형화하기 어렵다. Kim and Won(2004)은 이동성 호우의 경우 강우의 깊이-면적-지속기간(Rainfall Depth-Area-Duration)의 분석결과에서 상당한 오차를 야기하는 문제점을 지닌다고 주장하였다. 따라서 오차를 포함한 DAD의 산정결과는 가능최대강수량(Probable Maximum Precipitation, PMP) 및 가능최대홍수량 산정에도 영향을 미치기 때문에 정확도 높은 DAD 분석을 통한 PMF 산정이 요구된다. 본 연구에서는 유역을 선정하고 각 지점의 시계열 강우 자료를 활용하여 공간분포화한 강우자료에 격자기반의 자동 강우장 탐색기법을 이용하여 DAD 분석을 실시하였다. 기존의 PMP 산정방법에서는 한반도 전역에서 발생했던 130 mm이상의 호우사상을 선정한 후에 각 호우의 범위에 있는 우량관측소의 강우자료를 이용하여 PMP를 산정한다. 그렇기 때문에 만약 상대적으로 긴 지속기간의 경우 호우의 범위가 우리나라 전역을 포함할 가능성이 크기 때문에 PMP 산정방법은 복잡하고, 기상이변이 잦지 않는 지역에서 산정된 PMP를 이용하여 PMF를 산정할 경우, 유역의 특성을 반영하지 않았기 때문에 과대산정의 우려가 있다. 이에 따라 본 연구에서는 먼저 연구대상유역을 선정한 뒤, 유역 내에 발생했던 호우경보와 호우주의보를 기준으로 호우사상을 선정하여 DAD 분석 후 PMP를 산정하였다. 그 후, 강우-유출관계를 파악하여 PMF를 산정하였다.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.55 no.4
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• pp.312-318
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• 2010

This study was carried out to develop and test a prototype program that recommends the nitrogen topdressing rate using the color digital camera image taken from rice field at panicle initiation stage (PIS). This program comprises four models to estimate shoot N content (PNup) by color digital image analysis, shoot N accumulation from PIS to maturity (PHNup), yield, and protein content of rice. The models were formulated using data set from N rate experiments in 2008. PNup was found to be estimated by non-linear regression model using canopy cover and normalized green values calculated from color digital image analysis as predictor variables. PHNup could be predicted by quadratic regression model from PNup and N fertilization rate at panicle initiation stage with $R^2$ of 0.923. Yield and protein content of rice could also be predicted by quadratic regression models using PNup and PHNup as predictor variables with $R^2$ of 0.859 and 0.804, respectively. The performance of the program integrating the above models to recommend N topdressing rate at PIS was field-tested in 2009. N topdressing rate prescribed for the target protein content of 6.0% by the program were lower by about 30% compared to the fixed rate of 30% that is recommended conventionally as the split application rate of N fertilizer at PIS, while rice yield in the plots top-dressed with the prescribed N rate were not different from those of the plots top-dressed with the fixed N rates of 30% and showed a little lower or similar protein content of rice as well. And coefficients of variation in rice yield and quality parameters were reduced substantially by the prescribed N topdressing. These results indicate that the N rate recommendation using the analysis of color digital camera image is promising to be applied for precise management of N fertilization. However, for the universal and practical application the component models of the program are needed to be improved so as to be applicable to the diverse edaphic and climatic condition.

• The Journal of the Korea Contents Association
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• v.13 no.2
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• pp.400-411
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• 2013

OCB(organizational citizenship behavior) is a employee behavior that goes above and beyond the call of duty, that is discretionary and not explicitly recognized by the employing organization's formal reward system, and that contributes to organizational effectiveness. In a word, OCB has great potential as a organizational slack. As such, researchers have been showing great interest in the antecedents of OCB, and as a result, now we can meet so many antecedents of OCB from individual level variables to group or organizational level variables that are said to be important in explaining OCB. Additionally each of these variables is known to have its own sound logic and statistically significant effect on OCB. However the results of these studies are so fragmented that researchers have a great difficulty in drawing some meaningful or coherent conclusions. In this context, we try to applicate Q-methodology to find more coherent way of explaining the motives of OCB, and briefly speaking, we find four types of the motives of OCB, that is norm-based, instrumentality-based, trait-based, and avoidance-based type. Among these the last avoidance-based type is especially interesting, because we can't find any remarks on this type in the previous studies. The paper ends with suggestions for future research directions. We expect that these suggestions could be a foundation on which more developed and coherent OCB theories stand. We don't see this approach supplanting earlier efforts; rather we believe this can offer more detailed explanation in addition to those provided by other approaches.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.41 no.5
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• pp.477-484
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• 2021

Due to climate change, parts of Korea are experiencing large and small droughts every 2-3 years and extreme droughts every 7 years. Since most droughts occur mainly in areas where small water supply facilities in the tributaries or upstream are located, more research on technology for securing water in these areas is required. In this study, a drought evaluation using SPEI (Standardized Precipitation Evapotranspiration Index), SDI (Streamflow Drought Index), and WBDI (Water Budget-based Drought Index) was performed to investigate hydrological drought in the Mulrocheon watershed of Chuncheon, a vulnerable area in terms of water supply. As a result of calculating hydrological drought indices SPEI and SDI, examining each duration, it was confirmed that the common drought in 2014 did not recover and continued until 2015. In the hydrological drought index evaluation result by WBDI, a very severe drought condition was observed in the spring of 2015 following 2014, and that drought was the most severe at -1.94 in November 2017. As a result of deriving a SDF (Severity-Duration-Frequency) curve through frequency analysis by duration using the drought index calculated on a monthly basis from 2003 to 2019 (17 years), most droughts in the Mulrocheon watershed were found to have a return period of less than 10 years, but droughts that occurred in 2014, 2015, and 2019 were found to cover more than 20 years, respectively.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.9 no.5
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• pp.181-192
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• 2014

This study aims to analyze in relation to the influence and variable that their job instability and job stress attribute turnover intention to 134 employees of Midium and Small Firm less than 50 employees of a company being legal management at metropolitan area(Seoul, Kyeonggi-do, Incheon). To analyze a data, I took advantage of SPSS V.21, to analyze correlativity as each variable & causability, utilized bivariate correlation analysis & simple, multiple regression analysis, used sobel test as parameter effectiveness verification and post verification. This research result drew an conclusion to influence to turnover intention and stress perception from employment instability and job role stress of employees of Midium and Small Firm less than 50 employees being legal management, make of effect to the relation to stress perception and turnover intention indirectly. This result suggested the importance of stress management and human resource administration of employee of a Midium and Small Firm being legal management, drew an conclusion to attempt the research at first on employment instability and job stress of employees of Midium and Small Firm being legal management.

• Journal of the Korean Geographical Society
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• v.48 no.1
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• pp.56-71
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• 2013

The purpose of this study is to examine the spatial distributional characteristics of industries among the Korean cities and to conduct industry classification using the findings. For this purpose, 82 cities in Korea are investigated with respect to 15 industrial sectors. In the analysis, concentration of and association between industries are recognized using both geographic and non-geographic measures. In order to measure concentration and association, locational Gini coefficient, Moran's I, correlation coefficient, and bivatiate Moran are used and 15 industrial sectors are classified based on these estimates. The findings reveal that the chemical sector shows strong geographic and non-geographic concentrations while the assembly, machinery and electronics sector only shows a strong geographic concentration. Printing and publishing, wholesale, and business services show a strong non-geographic association with other sectors. The remaining ten sectors show no explicit distribution patterns among cities. This study contributes to providing the methodology that analyzes the spatial distribution patterns of industries in a comprehensive way and is able to provide useful information in implementing industrial location policies including industrial clusters.