• 천문학논총
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• 제35권3호
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• pp.29-41
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• 2020

Korea has numerous astronomical resources, such as observational records, star maps, and a wealth of literature, covering the period from the Three Kingdoms (54 BC - 932 AD) to the Joseon Dynasty (1392 - 1910 AD). The research activities related to these resources have been limited to those by individual researchers. It is now necessary to conduct research by efficiently and systematically collecting and managing Korean astronomical records using an accessible Web environment. The purpose of this study is to complete a system that enables researchers systematically to collect and verify a large number of historical records related to astronomical phenomena in a Web environment. In 2017, a preliminary survey was conducted, and the requirements pertaining to an implementation target system were devised. In addition, a joint development plan was carried out by the developer, lasting three months in 2018. Although the system is relatively simple, it is the first system to be attempted in the historical astronomy field. In order to proceed with the systematic development, the software development methodology is applied to the entire process from deriving the requirements of researchers to completing the system. The completed system is verified through integrated function and performance tests. The functional test is repeated while modifying and testing the system based on various test scenarios. The performance test uses a performance measurement test tool that takes measurements by setting up a virtual operation environment. The developed system is now in normal operation after a one-year trial period. Researchers who become authorized to use the system can use it to verify the accuracy of data and to suggest improvements. The collected feedback will be reflected in future systems, and Korean astronomical records will be available for use internationally through a multilingual service.

• 한국수자원학회논문집
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• 제46권3호
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• pp.287-299
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• 2013

본 연구의 목적은 기록된 관측가뭄자료를 이용하여 수문기상 기반의 국내 가뭄판단기준을 제시하는데 있다. 과거 1991년에서 2009년까지 기록된 가뭄사례를 수집한 후, 관측기상정보와 LSM(Land Surface Model)으로부터 생산된 수문정보를 이용하여 백분위 해석을 수행하였다. 기간별 가뭄판단기준을 도출하기 위해 객관적 가뭄평가 기법인 ROC(Relative Operating Characteristics) 분석을 이용하였다. 국내 가뭄기준은 대표적으로 강수 및 유출이 지속기간 3개월에 평년대비 35% 이하, 토양수분이 지속기간 2개월의 35% 이하 그리고 증발산량이 지속기간 3개월에 65% 이상으로 나타났다. 가뭄판단기준의 적용성 평가를 위해 SPI (3)와의 ROC 분석을 수행한 결과 SPI (3)에 비해 적용성이 높은 것으로 나타났다. 또한 가뭄판단기준에 대한 지역별 분석을 수행한 결과 공간적으로 가뭄상황을 적절히 반영하는 것을 확인하였다.

• 한국수자원학회논문집
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• 제49권2호
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• pp.145-153
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• 2016

본 연구에서는 우리나라에서 발생했던 과거 가뭄사상을 정량적으로 평가하기 위해 우리나라의 59개 기상관측소의 월강수량 자료를 이용하여 연강수량 및 계절별(봄철) 강수량에 대한 이상치($-1{\sigma}$)를 분석하였다. 연강수량을 통해 이상치 발생 빈도를 구하여 그 중 가장 유역별로 과우해($-1{\sigma}$) 발생빈도가 높은 이천, 거창, 정읍, 순천, 장흥 관측소를 선정하여 이상치를 분석한 결과 1988, 1994년이 동일하게 심한 과우해로 나타났다. 전체 이상치 기간 분석결과와 봄철 이상치 분석결과를 통해 2001년 가뭄은 심한 과우해로 분류되지는 않았지만 주로 섬진강 및 영산강 유역을 중심으로 심한 봄 가뭄이 발생하였으며, 농업용수 부족으로 인한 농작물 피해를 발생시킨 대표적인 농업적 가뭄연도로 분석되었다. 반면에 1981-1982년 및 1994-1995년과 같이 2년 이상 지속된 전국적 장기가뭄은 국가적으로 큰 가뭄피해를 야기하였다.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2010년도 학술발표회
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• pp.268-272
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• 2010

The research presented here represents a collaborative effort with the SFWMD on developing scenarios for future climate for the SFWMD area. The project focuses on developing methodology for simulating precipitation representing both natural quasi-oscillatory modes of variability in these climate variables and also the secular trends projected by the IPCC scenarios that are publicly available. This study specifically provides the results for precipitation modeling. The starting point for the modeling was the work of Tebaldi et al that is considered one of the benchmarks for bias correction and model combination in this context. This model was extended in the framework of a Hierarchical Bayesian Model (HBM) to formally and simultaneously consider biases between the models and observations over the historical period and trends in the observations and models out to the end of the 21st century in line with the different ensemble model simulations from the IPCC scenarios. The low frequency variability is modeled using the previously developed Wavelet Autoregressive Model (WARM), with a correction to preserve the variance associated with the full series from the HBM projections. The assumption here is that there is no useful information in the IPCC models as to the change in the low frequency variability of the regional, seasonal precipitation. This assumption is based on a preliminary analysis of these models historical and future output. Thus, preserving the low frequency structure from the historical series into the future emerges as a pragmatic goal. We find that there are significant biases between the observations and the base case scenarios for precipitation. The biases vary across models, and are shrunk using posterior maximum likelihood to allow some models to depart from the central tendency while allowing others to cluster and reduce biases by averaging. The projected changes in the future precipitation are small compared to the bias between model base run and observations and also relative to the inter-annual and decadal variability in the precipitation.

• Acta Via Serica
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• 제2권2호
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• pp.133-162
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• 2017

The Bering Strait crossing would link the entirety of Eurasia to the entirety of the Americas, and it can be seen as a natural extension of the historical Silk Road. There are some immense geopolitical benefits to such a project. It would bring about a profound and lasting change to the global economic and political outlook. The most valued function of the Bering Strait crossing and the extension of the associated railroad network would be to release the massive natural resources trapped underneath the tundra and permafrost for the benefit of Russia and the world. Moreover, the railroad project(s) would also build development corridors in those underdeveloped parts of the Russian Federation. The development of the resources and their rapid transportation to the global markets would contribute not only to the overall development of the region but also would be valuable for the resource-poor countries of Northeast Asia such as Japan, Korea, and China (relative to its economic size). This paper will explore the possible impact(s) of the Bering Strait crossing as a formidable infrastructure project for the economic development of the Russian Far East (RFE) from the Russian perspective under the frame of geopolitics. Furthermore, it will equally scrutinize the implications for the adjacent countries in the region.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2018년도 학술발표회
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• pp.176-176
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• 2018

This study presents a regional, probabilistic framework for estimating streamflow via spatial scaling in the Great Lakes basin, which is the largest lake system in the world. The framework follows a two-fold strategy including (1) a quadratic-programming based optimization model a priori to explore the model structure, and (2) a time-varying hierarchical Bayesian model based on insights found in the optimization model. The proposed model is developed to explore three innovations in hierarchical modeling for reconstructing historical streamflow at ungaged sites: (1) information of physical characteristics is utilized in spatial scaling, (2) a time-varying approach is introduced based on climate information, and (3) heteroscedasticity in residual errors is considered to improve streamflow predictive distributions. The proposed model is developed and calibrated in a hierarchical Bayesian framework to pool regional information across sites and enhance regionalization skill. The model is validated in a cross-validation framework along with four simpler nested formulations and the optimization model to confirm specific hypotheses embedded in the full model structure. The nested models assume a similar hierarchical Bayesian structure to our proposed model with their own set of simplifications and omissions. Results suggest that each of three innovations improve historical out-of-sample streamflow reconstructions although these improvements vary corrsponding to each innovation. Finally, we conclude with a discussion of possible model improvements considered by additional model structure and covariates.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2018년도 학술발표회
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• pp.150-150
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• 2018

The Numerical Weather Prediction (NWP) models provide information for weather forecasts. The highly nonlinear and complex interactions in the atmosphere are simplified in meteorological models through approximations and parameterization. Therefore, the simplifications may lead to biases and errors in model results. Although the models have improved over time, the biased outputs of these models are still a matter of concern in meteorological and hydrological studies. Thus, bias removal is an essential step prior to using outputs of atmospheric models. The main idea of statistical bias correction methods is to develop a statistical relationship between modeled and observed variables over the same historical period. The Model Output Statistics (MOS) would be desirable to better match the real time forecast data with observation records. Statistical post-processing methods relate model outputs to the observed values at the sites of interest. In this study three methods are used to remove the possible biases of the real-time outputs of the Weather Research and Forecast (WRF) model in Imjin basin (North and South Korea). The post-processing techniques include the Linear Regression (LR), Linear Scaling (LS) and Power Scaling (PS) methods. The MOS techniques used in this study include three main steps: preprocessing of the historical data in training set, development of the equations, and application of the equations for the validation set. The expected results show the accuracy improvement of the real-time forecast data before and after bias correction. The comparison of the different methods will clarify the best method for the purpose of the forecast skill enhancement in a real-time case study.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2020년도 학술발표회
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• pp.118-118
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• 2020

This study investigates the change of flow characteristics over 10 Asian river basins in the past 30 years (1976-2005). The variation is estimated from The Soil and Water Assessment Tool (SWAT) model outputs based on reanalysis data which was bias-corrected for Asian monsoon reagion. The model was firstly calibrated and validated using observed data for daily streamflow. Four statistical criteria were applied to evaluate the model performance, including Coefficient of determination (R2), Nash - Sutcliffe model efficiency coeffi cient (NSE), Root mean square error-observations standard deviation ratio (RSR), and Percentage Bias (PBIAS). Then parameters of the model were applied for the historical period 1976-2005. The estimates show a temporal non-considerable increasing rate of daily streamflow in most of the basins over the past 30 years. The difference of monthly discharge becomes more significant during the months in the wet season (June to September) in all basins. The seasonal runoff shows significant difference in Summer and Autumn, when the rainfall intensity is higher. The line showing averaged runoff/rainfall ratio in all basins is sharp, presenting high variation of seasonal runoff/rainfall ratio from season to season.

• 한국실내디자인학회:학술대회논문집
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• 한국실내디자인학회 2008년도 춘계학술발표대회 논문집
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• pp.285-289
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• 2008

There has been a project in Japan recently to develop the mixed-use facility in order to help regenerate its city's vitality. They must make efficient use of resources that contains historical and local identity. In contrast, Korea hasn't considered developing their mixed-use facilities for maintaining their historical identity. This research will analyze how locality is reflected in the 8 mixed-use facilities in Japan. The research method was as follows: Preparatory study and literature research were conducted to extract the elements of locality shown in the mixed-use facilities in Japan. According to the results, the peculiarities of locality are as follows: 1) It's important to make the most of the local Identity by reflecting on the historical peculiarity of the region. 2) Nature and its environmental surroundings should be considered when constructing buildings in order to revitalize its local identity. 3) In the perception aspect, when a mixed-use facility is open for visit, the negative elements such as the 'peripheral regional gap' that may be felt by the visitor must be kept to the minimum.

• 상하수도학회지
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• 제30권6호
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• pp.699-705
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• 2016

Although it has been well known that the Saemaul Undong had a direct relation with the water resources development during 1970's, its contribution to the water resources and increased income in rural communities has not been thoroughly quantified so far. In order to assess the contribution of the Saemaul Undong in terms of rural water resources development, we investigated various historical data produced by the central and local governments in relation to water resources development. The results show the direct and indirect contribution of the Saemaul Undong to the water resources development in rural communities such as sewage works, water supply facilities, shared wells, and river works. The results also showed a positive relation between per-house income in rural communities and areas of irrigated paddies, which were rapidly increased during 1970's. These results can be utilized to transplant the positive aspect of the Saemaul Undong to developing countries focusing on water resources development in rural areas.