• Journal of Korea Water Resources Association
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• v.50 no.2
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• pp.75-87
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• 2017

In recent decades, extreme events have been significantly increased over the Korean Peninsula due to climate variability and climate change. The potential changes in hydrologic cycle associated with the extreme events increase uncertainty in water resources planning and designing. For these reasons, a reliable changing point analysis is generally required to better understand regime changes in hydrologic time series at watershed scale. In this study, a hierarchical changing point analysis approach that can apply in a watershed scale is developed by combining the existing changing point analysis method and hierarchical Bayesian method. The proposed model was applied to the selected stations that have annual rainfall data longer than 40 years. The results showed that the proposed model can quantitatively detect the shift in precipitation in the middle of 1990s and identify the increase in annual precipitation compared to the several decades prior to the 1990s. Finally, we explored the changes in precipitation and sea level pressure in the context of large-scale climate anomalies using reanalysis data, for a given change point. It was concluded that the identified large-scale patterns were substantially different from each other.

• Korean Journal of Social Welfare Studies
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• v.43 no.1
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• pp.143-178
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• 2012

This study analyzed the changes of welfare and labor market status of participants of Self-sufficiency Support Program in Korea thorough of analysis follow-up data which were collected about the experiences and changes of participants of the program in Gyeonggi province in 2005. As the results, many of participants exited from the program within five years, and hardly anyone depends on the welfare or the program, also there is very little the revolving door phenomenon. Whatever, the program have positive effects the changes of welfare and labor market status of them. Also, self-sufficiency communities, the small enterprises are started by more two participants and aim the economic independence of them and contribution to social economy have played important role for their persistent work and economic self-reliance. The people exited from the program, however, hardly succeed in exit from the welfare and their economic conditions still are not good. Therefore, we have to arrange the program for the participants' self-sufficiency, and we rather have to effort to secure their economic well-being than emphasize the immediately employment or establishment a business.

• Proceedings of the Korea Water Resources Association Conference
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• 2020.06a
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• pp.84-84
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• 2020

새만금은 농업용지 확보 등 다양한 용도의 토지이용을 목적으로 방조제 공사를 수행하였으며, 새만금 종합개발계획(Master Plan, OPC, 2011)에 의하여 호내의 준설을 계획하고 있다. 그러나 방조제 준공 후 새만금 호내의 수질오염 문제가 지속적으로 발생되어 왔다. 수질오염의 문제를 해결하기위해서 강변저류지 설치, 하수종말 처리장 등 다양한 구조적 대책이 수립되고 시행되었지만, 수질개선 효과는 상대적으로 미비하였다(Kim et al, 2016; KRCC, 2016). 본 연구에서는 새만금 호내의 수질개선을 위하여, 다양한 배수갑문 운영에 따른 수질인자의 잔존률 및 하상의 변화를 SCHISM-CoSiNE(Semi-implicit Cross-scale Hydroscience Integrated System Model and Carbon, Silicate, Nitrogen Ecosystem model) 모형을 통하여 검토하고자 한다. 수치모형의 하상변동 및 수질변화에 대한 정확한 수치계산 여부를 판단하기 위하여 van Rijn(1987) 실험 및 새만금호내의 수질 관측자료(DO, T-N, T-P, 온도, 염도, 새만금유역 통합환경관리시스템)를 이용하여 수치모형 검증을 수행하였고 10% 이내의 오차를 나타내었다. 배수갑문 운영기록(Jeong et al., 2018)을 참조하여 배수갑문 운영을 재현하였으며, 지형은 기 수립된 MP 내 새만금 종합개발계획이 완료된 시점인 2030년을 기준으로 하였다. 수치모의를 통하여, 배수갑문 운영 및 계절의 변화에 따른 최심 하상변동고 변화 및 하상변동량을 확인하여 침식 퇴적 구간을 구분하였고, 호내의 잔존하는 수질인자의 농도를 통하여 수질개선 효과를 평가하여 수질측면에서 최적의 배수갑문 운영방안을 제시하였다. 본 연구는 배수갑문 운영이 새만금 호내의 수질 및 지형에 미치는 영향에 대한 기초적인 연구이지만 향후에는 다양한 수질인자 및 시나리오를 고려한다면 보다 근본적인 수질오염 해결방안으로 활용이 가능할 것으로 판단된다.

• Journal of Radiation Protection and Research
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• v.25 no.4
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• pp.207-216
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• 2000

Continuous measurements of radon progeny concentrations in the open atmosphere and measurements of meteorological parameters were performed in Tajeon, using a continuous gross alpha/beta aerosol monitor and a weather measuring equipment between July 1999 and July 2000. These data were analyzed for half-hourly, daily, and seasonal variations. The distribution of daily averaged equilibrium equivalent radon concentration$(EEC_{Rn})$ had an arithmetic mean value of $11.3{\pm}5.86Bqm^{-3}$ with the coefficient of variation of about 50% and the geometric mean was $10.3Bqm^{-3}$. The $EEC_{Rn}$ varies between 0.83 and $43.3Bqm^{-3}$, depending on time of day and weather conditions. Half-hourly averaged data indicated a diurnal pattern with the outdoor $EEC_{Rn}$ reaching a maximum at sunrise and a minimum at sunset. The pattern of the seasonal variation of the $EEC_{Rn}$ in Taejon had a tendency of minimum concentration occurring in the summer(July) and maximum concentration occurring in the late autumn(November). But the seasonal variation of the $EEC_{Rn}$ is expect to vary greatly from place to place. The outdoor $EEC_{Rn}$ was highly dependent on the local climate features. Particularly the $EEC_{Rn}$an rapidly drops less than $5Bqm^{-3}$ in case of blowing heavily higher than wind speed of $6msec^{-1}$, reversely the days with more than $30Bqm^{-3}$ were at a calm weather condition with the wind speed of lower than $1msec^{-1}$.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.1
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• pp.468-476
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• 2020

This study investigated how latent groups depend on the longitudinal trajectories observed in fathers' involvement in parenting over a five year period, and the study also determined differences in children's behavioral problems and mother's parenting stress, marital satisfaction, and depression among these groups. By utilizing 1,316 sets of data from 1st to 5th Panel Survey of PSKC beginning in 2008, we examined the patterns of the latent groups and the differences among them. The results showed that, first, a changing pattern of fathers' involvement in parenting is classified into four groups: a low-stable group, a decreasing group. a middle-high changeable group, and a highest changeable group. According to the results of the latent groups, the fathers' involvement in parenting commonly started to decrease at the children's age of 4 years old. Second, problematic behaviors of children appeared more from the fathers in the decreasing group. Third, parenting stress, marital conflict, and depression were more often found in the low-stable group that in the decreasing group. the middle-high changeable group and the highest changeable group (in that order), while marital satisfaction showed a completely opposite pattern. Based on these results, political intervention and the future direction of research for fathers' involvement in parenting are needed in order to increase better behaviors of their children as well as the psychological well-being of their mothers.

• The Journal of Engineering Geology
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• v.23 no.4
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• pp.353-361
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• 2013

To analyze the distribution of earthquake-induced strain data in rock masses, statistical analysis was performed on four-directional strain data obtained from a ground movement monitoring system installed in Korea. Strain data related to the 2011 Tohoku-oki earthquake and two aftershocks of >M7.0 in 2011 were used in x-MR control chart analysis, a type of univariate statistical analysis that can detect an abnormal distribution. The analysis revealed different dispersion times for each measurement orientation. In a more comprehensive analysis, the strain data were re-evaluated using multivariate statistical analysis (MSA) considering correlations among the various data from the different measurement orientations. $T_2$ and Q-statistics, based on principal component analysis, were used to analyze the time-series strain data in real-time. The procedures were performed with 99.9%, 99.0%, and 95.0% control limits. It is possible to use the MSA data to successfully detect an abnormal distribution caused by earthquakes because the dispersion time using the 99.9% control limit is concurrent with or earlier than that from the x-MR analysis. In addition, the dispersion using the 99.0% and 95.0% control limits detected an abnormal distribution in advance. This finding indicates the potential use of MSA for recognizing abnormal distributions of strain data.

• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.781-784
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• 2008

현재 한강수계에서는 북한강 상류에 건설된 임남댐(저수용량 26억$m^3$)으로 인하여 화천댐 상류 유역계의 변화가 발생하였다. 화천댐의 경우, 기존의 발전용량을 포함한 안정적 방류계획에 변화가 발생하여 기존 저수지 용량의 효율적인 관리기술의 실증이 필요한 시점이다. 또한, 향후 기후변화 및 용수이용 증가에 대비한 안정적인 물공급을 위해 하천유출량의 시 공간적인 평가 및 가용수자원의 평가는 보다 합리적이고 정확하게 이루어져야 하며, 이를 위해 준분포형 유역유출-저수지 운영 결합해석 모형이 필수적으로 도입되어야 할 시점이다. 따라서, 본 연구에서는 SWAT-K(과학기술부, 2007)를 이용하여 기존댐의 최적 운영룰을 도출한 후, 팔당호에서의 유황개선 효과를 정량적으로 분석하여 수자원 확보량을 평가하고자 하였다. 화천댐의 경우, 방류시나리오로 기존 운영실적을 기준으로 홍수기 중 9월 방류량을 50% 감소, 비홍수기 중 $11{\sim}3$월 방류량을 50% 증가시켜 적용하였을 때 최적 운영룰이 도출되었으며, 이때 갈수량 이하의 10일간 유황개선을 통하여 분석기간에 대하여 0.12억$m^3$의 수자원 확보가 이루어질 수 있었다.

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.285-285
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• 2023

기후변화로 인한 변동성의 증가는 돌발 홍수, 홍수량 증가로 이외에도 강우 사상의 변화, 가뭄의 빈도 및 강도의 증대 등의 문제를 이어질 수 있다. 이러한 기후변화에 대응하기 위하여 기후변화 시나리오를 제시하고 이를 정책적으로 반영할 수 있도록 하고 있다. 기존 IPCC 5차 보고서에 활용한 RCP(Representative Concentration Pathway) 시나리오에서는 온실가스 농도변화만을 반영하고 있으나, 최근 IPCC 6차 보고서에서는 사회적인 노력과 경제적 구조 등 전반적인 기후정책, 사회 불균형 등을 고려한 SSP(Shared Socio-economic Pathways) 시나리오를 제시하였다. 본 연구에서는 2가지 기후변화 시나리오의 차이점과 유사점을 강수 중심으로 평가하였다. 기존의 RCP 시나리오에 비하여 극한 강우 사상의 변화를 비교 및 평가하기 위하여 CORDEX-EA에서 제공하는 지역기후모델(Regional Climate Model; RCM) 기반에 시나리오를 수집하여 극한기후지수를 산정하였다. 극한기후사상을 비교하기 위하여 WMO에서 활용하는 ETCCDI(Expert Team on Climate Change Detection and Indices) 지수 중 강우 관련 지수인 R10mm, RX1day, RX5day, RD95P, RD99P, SDII를 선정하여 시나리오 별로 결과를 비교하여 제시하였다. 또한, 기존의 연대기 기준의 평가방식에서 탈피하여 동일한 기온 상승 시점에 따라 변화를 확인하기 위한 분석절차를 수립하였다. 즉, 1.5℃, 2℃, 3℃ 및 4℃ 상승한 시점의 ETCCDI 지수를 산정하여 극한기후사상을 비교 및 평가하였다.

• Proceedings of the Korea Information Processing Society Conference
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• 2022.05a
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• pp.448-451
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• 2022

주식과 암호화폐 거래는 매매방식에 있어서 유사한 점이 있지만 기업의 사업분야, 자본금, 순이익 등의 경영현황과 미래가치에 영향을 많이 받는 주식과는 다르게 암호화폐는 실물 실체가 없으며 탈중앙화, 전산화된 데이터를 기반으로 하며 심리적인 요소가 크게 작용하여 단기적인 변동이 클 수 있다. 본 연구에서는 이러한 암호화폐 거래의 특성을 활용하여 특정 암호화폐에 관련된 뉴스기사들을 수집하고 그 암호화폐의 가격 변화 데이터와 연관되어 가격예측 딥러닝 모델을 생성하고 해당 암호화폐에 대한 신규 뉴스기사가 발생되었을 때 이를 이용하여 매수, 매도, 관망 등과 같은 매매 정보를 예측 적용할 수 있게 하였다. 첫째, 뉴스 기사에서 언급한 암호화폐를 매수, 매도, 관망 중 어느 편이 좋을 것인지 추천하는 알고리즘을 구현하였고, 둘째, 매수 이후 매매 차익을 위한 매도 시점이나 매도 이후 저가매수에 유리한 시점을 제안하는 알고리즘을 구현하였다. 또한, 실시간 뉴스기사 수집 및 예측한 매매 판단에 따라 매매 자동화 시스템을 구현하여 수익률을 직접 확인함으로써 그 유효성을 검증하였다.

• Korean Journal of Agricultural and Forest Meteorology
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• v.17 no.2
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• pp.182-189
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• 2015

Climate departure from the past variability was projected to start in 2042 for Seoul. In order to understand the implication of climate departure in Seoul for urban agriculture, we evaluated the daily temperature for the June-September period from 2041 to 2070, which were projected by the RCP8.5 climate scenario. These data were analyzed with respect to climate extremes and their effects on growth of hot pepper (Capsicum annuum), one of the major crops in urban farming. The mean daily maximum and minimum temperatures in 2041-2070 approached to the $90^{th}$ percentile in the past 30 years (1951-1980). However, the frequency of extreme events such as heat waves and tropical nights appeared to exceed the past variability. While the departure of mean temperature might begin in or after 2040, the climate departure in the sense of extreme weather events seems already in progress. When the climate scenario data were applied to the growth and development of hot pepper, the departures of both planting date and harvest date are expected to follow those of temperature. However, the maximum duration for hot pepper cultivation, which is the number of days between the first planting and the last harvest, seems to have already deviated from the past variability.