석정(石亭) 이정직(李定稷)의 생애(生涯)와 저술(著述) 및 교유관계(交遊關係)

朴徹庠 ( Park¸ Chul-sang ) 성균관대학교 대동문화연구원 2021 大東文化硏究 Vol.115 No.-

석정 이정직은 조선 말기의 書畵家이자 學者이다. 그에 관한 많은 연구가 이뤄졌고, 그의 서화를 소개하는 전시회 또한 여러 차례 열렸다. 그러나 이들 연구와 전시회에 소개된 이정직에 관한 정보는 많은 오류를 내포하고 있다. 게다가 이정직이 주로 전주와 김제 지역에서 활동했기 때문에 그의 교유 인물들에 관한 정보도 빈약했다. 이는 이정직 연구의 걸림돌이 되고 있다. 본 논고에서는 먼저 이정직의 생애와 저술에 관해 검토하였다. 새로운 자료를 통해 이정직에 관한 보다 정확하고 풍부한 정보를 제공하였다. 다음으로 이정직의 교유관계를 살펴봤다. 기존에는 黃玹과 李沂를 중심으로 이정직의 교유관계를 다뤘지만, 여기서는 이들을 제외한 인물들을 중심으로 소개하였다. 특히 이건창과의 교유는 새롭게 소개되는 부분이다. 이 밖에도 이정직의 교유 인물을 지역별로 간략히 정리하였다. Seokjeong(石亭) Lee Jeong-Jik(李定稷) was a calligrapher, painter and scholar of the late Joseon Dynasty. A lot of research was done on him, and exhibitions introducing his paintings were also held several times. However, the information about Lee Jeong-Jik introduced in these studies and exhibitions contains many errors. Furthermore, information on Social Intercourse was poor as he was mainly active in Jeonju and Gimje. This is a stumbling block to the research of Lee Jeong-Jik. In this essay, I first reviewed the life of Lee Jung-jik and his writings. I used new data to provide more accurate and rich information about Lee Jeong-Jik. Next, I looked at the social intercourse of Lee Jung-jik. Previous studies focused on the relationship of Lee Jung-jik with Hwang Hyeon(黃玹) and Lee Ki(李沂), but I introduced people except them. In particular, it introduced the relationship with Lee Geon-chang(李建昌) for the first time. In addition, a brief summary of social intercourse of Lee Jung-jik was compiled by region.

Multi-Dimensional Precipitation Models and Their Application of the Ground-Truth Problem : Multiple Raingauge Case

Chulsang Yoo,Eunho Ha 대한토목학회 2001 KSCE journal of civil engineering Vol.5 No.1

Multi-Dimensional Precipitation Models and Their Application to the Ground-Truth Problem

Chulsang Yoo,Eounho Ha 대한토목학회 1998 KSCE journal of civil engineering Vol.2 No.4

On Optimal Sampling Design for Rainfall Field

Chulsang Yoo 대한토목학회 2006 KSCE journal of civil engineering Vol.10 No.1

This paper reviews the sampling error formalism by North and Nakamoto (1989), North et al. (1991), and Yoo (2000) to provide an idea of optimal sampling design for rainfall field. Rain gauge networks, a line of rain gauges, microwave attenuation measurements, and satellite measurements are evaluated. Combined sampling cases using any two different sampling methods are also evaluated. All cases are applied to the GATE Phase I data, the same as in North and Nakamoto (1989), for the comparison. Summarizing the results is as follows. (1) Without any consideration of heterogeneities like orographic effect or diurnal cycle, the most economical rain gauge network becomes to use evenly spaced 16 gauges or satellite sampling every 24 hours for the sampling of 500km x 500㎞ area of GATE. For both cases the sampling error was estimated to be about 10% of standard deviation of areal average values. (2) The sampling error could be decreased significantly for the combined sampling of two different sensors, especially when they satisfy the condition for design orthogonality. For example, the sampling error is decreased up to 50% by combining the evenly spaced 16 rain gauges with satellite sampling every 24 hours.

USE OF THE KALMAN FILTER FOR THE CORRECTION OF MEAN-FIELD BIAS OF RADAR RAINFALL

CHULSANG YOO,JUNGHO KIM,JUNGSOO YOON,CHEOLSOON PARK,CHANGYEOL PARK,CHANGHYUN JUN 한국기상학회 2011 한국기상학회 학술대회 논문집 Vol.2011 No.10-2

Evaluation of Error Indices of Radar Rain Rate Targeting Rainfall-Runoff Analysis

Yoo, Chulsang,Ku, JungMo,Yoon, Jungsoo,Kim, Jungho American Society of Civil Engineers 2016 Journal of hydrologic engineering Vol.21 No.9

<P>This study evaluates several error indices of the radar rain rate from the viewpoint of the accuracy of rainfall-runoff analysis. The error indices considered in this study are the mean error (ME), mean absolute error (MAE), normalized standard deviation (NSD), correlation coefficient (CC), bias (BS), and radar rain rate quality criterion (RRQC). These indices were analyzed using the concept of sum of squares (SS) and mean squares (MS) in the analysis of variance (ANOVA), which explains how the bias and random error of the radar rain rate are combined in an error index. Also, these error indices were linked to the errors in the runoff result, such as the total runoff volume, peak flow, and peak time. As an application, two dam basins in Korea were selected, the Chungju Dam basin and the Namgang Dam basin. The radar rain rates from Gwangdeoksan Radar and Gudeoksan Radar were used as input for the rainfall-runoff analysis. Six different rainfall events were applied to secure various rainfall types. As a result, it was found that ME, BS, and RRQC were linearly proportional to the errors in the runoff result. This result indicates that the bias plays a dominant role in the evaluation of the radar rain rate, targeting the rainfall-runoff analysis.</P>

가우시안 프로세스 기반 함수근사와 서포트 벡터 학습을 이용한 레이더 및 강우계 관측 데이터의 융합

유철상(Chulsang Yoo),박주영(Jooyoung Park) 한국지능시스템학회 2008 한국지능시스템학회논문지 Vol.18 No.3

최근들어, 커널 기법(kernel method)은 패턴 분류, 함수 근사 및 비정상 상태 탐지 등의 분야에서 상당한 관심을 끌고 있다. 특히, 서포트 벡터 머신(support vector machine)이나 커널 주성분 분석(kernel principal component analysis) 등의 방법론에서 커널의 역할은 매우 중요한데, 이는 고전적인 선형 머신이 비선형성을 효과적으로 다룰 수 있도록 일반화 해줄 수 있기 때문이다. 본 논문에서는 커널 기반 가우시안 프로세스(gaussian process) 함수근사 기법과 서포트 벡터 학습을 이용하여 레이더와 강우계의 관측 데이터를 융합하는 문제를 고려한다. 그리고, 국내의 강원, 경북 및 충북에 걸쳐있는 지역에 대한 레이더 자료 및 강우계 자료를 대상으로 하여 본 논문에서 고려하는 방법론들에 의해 데이터 융합을 수행한 결과를 제시하고, 성능비교를 수행한다. Recently, kernel methods have attracted great interests in the areas of pattern classification, function approximation, and anomaly detection. The role of the kernel is particularly important in the methods such as SVM(support vector machine) and KPCA(kernel principal component analysis), for it can generalize the conventional linear machines to be capable of efficiently handling nonlinearities. This paper considers the problem of combining radar and rain gauge observations utilizing the regression approach based on the kernel-based gaussian process and support vector learning The data-assimilation results of the considered methods are reported for the radar and rain gauge observations collected over the region covering parts of Gangwon, Kyungbuk and Chungbuk provinces of Korea, along with performance comparison.

Theoretical evaluation of concentration time and storage coefficient with their application to major dam basins in Korea

Yoo, Chulsang,Lee, Jiho,Cho, Eunsaem IWA Publishing 2019 Water science & technology--water supply Vol.19 No.2

<P>This study theoretically evaluated the basin concentration time and storage coefficient with their empirical formulas available worldwide. The evaluation results were also validated in the application to major dam basins in Korea. The findings are summarized as follows. As a result of analytical analysis, the concentration time was found to be proportional to the main channel length under laminar flow conditions and to the square of it under turbulent flow conditions, but inversely proportional to the channel slope. It was also found that the storage coefficient and the concentration time are linearly but loosely related. Most empirical formulas for the concentration time concurred with the basic equation form, but just a few for the storage coefficient. Applications to major dam basins in Korea also showed that the concentration time agrees well with the result of theoretical analysis. However, the behavior of the storage coefficient varied much, basin by basin, indicating that additional factors may be needed to explain it.</P>

Evaluation of the gap filler radar as an implementation of the 1.5 km CAPPI data in Korea

Yoo, Chulsang,Yoon, Jungsoo,Kim, Jungho,Ro, Yonghun John Wiley Sons, Ltd 2016 Meteorological applications Vol.23 No.1

<P><B>ABSTRACT</B></P><P>This study evaluated the gap filler radar as an implementation of the 1.5 km CAPPI (constant altitude plan position indicator) data in Korea. The use of the 1.5 km CAPPI data was an inevitable choice, given the topography of the Korean Peninsula and the location of the radar. However, there still exists a significant portion of beam blockage, and thus there has been debate about the need to introduce the gap filler radar (or, the gap‐filler). This study evaluated the possible benefits of introducing gap‐fillers over the Korean Peninsula. As a first step, the radar data error was quantified by <I>G</I>/<I>R</I> ratio and root mean square error (RMSE), and the radar data over the Korean Peninsula were evaluated. The gap‐fillers were then located where the error was high, and their effect was then evaluated by the decrease in the <I>G</I>/<I>R</I> ratio and RMSE. The mean values of the <I>G</I>/<I>R</I> ratio and RMSE of the 1.5 km CAPPI data over the Korean Peninsula were estimated to be about 2.5 and 4.5 mm h<SUP>–1</SUP>, respectively. Even after the mean‐field bias correction, the RMSE of the 1.5 km CAPPI data was not decreased and mostly remained very high, around 4.4 mm h<SUP>–1</SUP>. Unfortunately, the effect of the gap‐filler on the 1.5 km CAPPI data was also found to be very small, just 1–2%. However, the gap‐filler could be beneficial, if the lowest elevation angle data were used instead of the 1.5 km CAPPI data. The effect of five gap‐fillers could be up to 7% decrease in RMSE.</P>

Broken-Line Model of Dam Storage and Evaluation of Water Supply Safety Using a Bivariate Frequency Analysis

Yoo, Chulsang,Jun, Changhyun American Society of Civil Engineers 2017 Journal of water resources planning and management Vol.143 No.10

<P>In this study, a new evaluation method for the water supply safety of a dam is proposed. This method considers both climatic conditions and storage characteristics of a dam. The annual variation of dam storage is represented by a broken-line model, the lines of which are determined by only three-factors: the monthly design water supply during the dry period; dam storage at the end of the dry period; and changes in dam storage during the wet period. From the results of bivariate frequency analysis, a unique broken-line model is derived under multiple scenarios with the given return periods for the evaluation of water supply. The proposed method is applied to a total of five major dams in Korea. It is shown that the water supply safety of a dam can be quantified by using the concept of the return period, and five major dams have water supply safety corresponding to return periods of 10-50 years. Among them, the Soyanggang Dam is found to be the most stable with respect to water supply safety in Korea. (c) 2017 American Society of Civil Engineers.</P>