• (The)Study of the Eastern Classic
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• no.62
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• pp.37-65
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• 2016

This paper is to explain who are the authors of first-half 18th Century private prose YeonHangRok(燕行錄) written in Chinese Character and what are interest-oriented aspects of that books. As objects of study, 3 private prose YeonHangRok(燕行錄) written by No-Ron Jeon -Ju Lee's Family(老論 全州李氏) were chosen. Result of reading articles in their anthology, I found their consciousness about going to Beijing. : They aware of "The importance of YeonHang(燕行)" and when they run a mission, they take an attitude of 'observation and attention' to their experience. With that consciousness of YeonHang(燕行) in common, So-jae(疎齋), Il-am (一菴) and Hanpojae(寒圃齋) wrote their YeonHangRok(燕行錄) that mainly describe their direct experience. So-jae(疎齋) and Hanpojae(寒圃齋)'s categories of descriptions are specialized in 'Public Affairs' and 'mission', Il-am(一菴) has widened to the everyday cultures and people of Other cultures.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.4
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• pp.2419-2427
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• 2014

This paper defines the hydro-geomorphological river area to estimate the change of the river function before/after levee construction, and proposes the methodology that calculates the river area by using GIS. The boundary of river area is determined by the 100-year potential flood inundation area without the levee effect of the flood protection. Firstly, 1918' land-use map was digitized and the changes were analyzed by comparing with 2007' digitized map. The result shows that urban/farmland zone in Mankyung river area were increased by 0.4%/11.6% and bare ground was decreased by 10.0% so that the effective use of floodplain due to levee construction leaded to better productivity, but the decrease of the environment function of the river was predicted as result of the reduction of the river area.

• The Korean Journal of Applied Statistics
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• v.28 no.6
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• pp.1133-1146
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• 2015

The Horse race industry has the largest proportion of the domestic legal gambling industry. However, there is limited statistical analysis on horse races versus other sports. We propose prediction models for winning horses in horse races using data mining techniques such as logistic regression, linear regression, and random forest. Horse races data are from the Korea Racing Authority and we use horse racing reports, information of racehorses, jockeys, and horse trainers. We consider two models based on ranks and time records. The analysis results show that prediction of ranks is affected by information on racehorses, number of wins of racehorses and jockeys. We place wagers for the last month of races based on our prediction models that produce serious profits.

• Ecology and Resilient Infrastructure
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• v.6 no.4
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• pp.314-327
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• 2019

This study investigates channel stabilities with groynes by developing the assessment of it and applying a 2-dimensional numerical model, which simulates flow and sediment transport with various flows in the channel. Evaluation inventories are composed of five items, which are width to depth ratio, sinuosity, bed slopes, velocities in the flow flied, Shields number with discharges and geomorphic characteristics in the study reach. The channel stability is evaluated by applying the evaluation indicators to the channel with and without groynes in the study reach between Dalseong-weir and Gangjeonggoryeong-weir in the Nakdong river. Width to depth ratio, sinuosity, and bed slopes, which are index of river characteristics, little affect the channel stability. However, velocities in the flow flied, and Shields number, which is dimensionless tractive, near the banks of the channel strongly affect the stability. The evaluation values of the stability in the channel on the left and right banks decrease as the number of groynes increase in both the left and right banks, which means that the bank stability increases with the groynes.

• Journal of the Society of Disaster Information
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• v.18 no.3
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• pp.600-608
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• 2022

Purpose: The purpose of this study is to examine the types of crimes taking place using NFT in P2E games, and to devise measures to prevent crimes and legal sanctions between the government and companies. Method: In order to classify crime types in the metaverse, crime types were analyzed based on the results of previous studies and current incidents. Results: Most of the crimes taking place through NFTs in P2E games are hacking, money laundering, and copyright issues. Although games are regulated in Korea, these are crimes that can occur if game regulations are loosened in the future. Therefore, crime types were classified into hacking, money laundering, tax evasion, copyright issues, and game speculation, and various cases of damage have already occurred in foreign countries. Conclusion: Currently, no crimes are occurring in Korea due to game regulations, but as seen in foreign cases, large amounts of hacking and money laundering using NFTs are taking place in Korea. this will have to be provided

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.501-501
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• 2023

하천에서의 여가활동에 대한 수요가 증가함에 따라 각종 친수활동에 대한 안전도 평가가 사고예방을 위해 중요해지고 있다. 친수 활동의 안전은 수리 및 수질 인자에 크게 영향을 받지만 기존 친수지수는 수질 인자에만 집중되어 개발되어왔다. 하지만, 세일링, 패들링, 저동력보트 등 입수형 친수활동의 경우, 다양한 수리 현상에 큰 영향을 받기 때문에 유속, 흐름 방향, 수심 및 수면 폭 등의 수리인자를 친수지수에 반영할 필요가 있다. 또한, 친수활동에 위험이 되는 수리적 조건은 유량 조건과 하천의 평면적 공간에 따라 상이하게 발생하기에 이를 공간적으로 평가하는 것 역시 필요한 실정이다. 본 연구에서는 수리학적 요소를 기반으로 하천 친수 활동에 대한 안전도를 평가하기 위해 공간적으로 친수활동의 안정성을 평가할 수 있는 SRRI (Spatial River Recreation Index)를 제안하였다. SRRI의 개발을 위해 1단계에서는 다양한 유량 조건에서 EFDC 동수역학모형을 이용하여 수리 인자들의 공간적 분포를 재현한 후, 2단계에서는 퍼지합성법 (FSE)를 적용하여 수리인자의 모든 소속도와 가중치를 종합하여 하천 지점별 하천친수지수를 산정하였다. 개발한 SRRI를 낙동강-금호강 합류부에 적용한 결과, 유량 및 지형 조건에 따라 각 수리인자가 친수활동 안전성에 미치는 영향이 공간적으로 매우 상이하게 나타났다. 유향(흐름 방향)은 합류지점 부근에서 친수활동의 위험성을 크게 증가시키는 반면, 사행구간에서는 수심이 중요한 요인으로 나타났다. 고유량 조건에서는 유속이 세일링 및 패들링에서 가장 큰 영향을 미치는 요소로 작용하였다. 특히 세일링은 유량 변화에 민감하여 고유량시에는 주흐름부와 합류부 부근을 제외하고 일부 공간에서만 안전하게 이용이 가능한 것으로 나타났다. 반면 무동력 및 저동력보트는 유량 변화에 덜 민감하여 고유량 조건에서도 부분적으로 허용될 수 있었지만 사행구간의 고수심부에서는 위험 등급으로 권고되었다. 이러한 결과를 바탕으로 SRRI는 다양한 수리학적 조건을 기반으로 공간적 안전정보를 제공함으로써 많은 이용자들이 하천에서 보다 안전한 친수활동을 즐기는 데에 기여할 수 있을 것으로 판단된다.

• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.1757-1760
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• 2008

본 연구에서는 유한요소 모델인 RMA-2를 이용하여 격자의 구성방법에 따른 만곡수로에서의 흐름특성분석을 비교하였다. 수치모의는 격자구성에 따라 균일격자망의 모형과 타원형 편미분 방정식을 이용한 모형에 대하여 실시하였다. 균일 격자망의 모형은 직선부에서는 가로세로비율에 따라 직사각형 격자를 구성하였고 곡선부에서는 곡률구간을 일정한 각도로 나누어 구성하였으며, 타원형 편미분 방정식을 이용한 모형은 격자간의 직교성을 만족하도록 구성하였다. 본 연구의 수치 모의는 Shukry(1950)의 $180^{\circ}$ 만곡수로실험과 동일한 조건으로 실시하였으며 각 지점에서의 합성 유속분포를 실험값과 비교하였다. 실험결과, 만곡부에서 타원형 편미분 방정식을 이용한 모형의 수치모의 결과는 균일격자를 이용한 모형에 비해 실험값과 잘 일치함을 알 수 있었다.

• Proceedings of the Korean Society of Computer Information Conference
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• 2020.07a
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• pp.531-533
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• 2020

게임 시장에서는 다양한 형태로 확률형 아이템을 판매하고 있다. 그 중 확률형 아이템은 게임사의 주요 수입원이다. 그러나 유저들에게는 확률형 아이템의 랜덤성 때문에 게임을 즐기는 데 있어서 스트레스를 받고 정확하지 않은 과금액과 사행성이 담겨 있는 판매 방식으로 인해 혹평을 내놓는다. 본 논문에서는 설문을 기반으로 유저가 확률형 아이템의 어느 부분에 불만이 있는지 구체적으로 제시하여 기업이 유저들의 불만을 파악하고 줄이는데 도움을 주고자 한다.

• Journal of Korea Water Resources Association
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• v.50 no.7
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• pp.455-465
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• 2017

Understanding of the two-dimensional velocity field is crucial in terms of analyzing various hydrodynamic and fluvial processes in the riverine environments. Until recently, many numerical models have played major roles of providing such velocity field instead of in-situ flow measurements, because there were limitations in instruments and methodologies suitable for efficiently measuring in the broad range of river reaches. In the last decades, however, the advent of modernized instrumentations started to revolutionize the flow measurements. Among others, acoustic Doppler current profilers (ADCPs) became very promising especially for accurately assessing streamflow discharge, and they are also able to provide the detailed velocity field very efficiently. Thus it became possible to capture the velocity field only with field observations. Since most of ADCPs measurements have been mostly conducted in the cross-sectional lines despite their capabilities, it is still required to apply appropriate interpolation methods to obtain dense velocity field as likely as results from numerical simulations. However, anisotropic nature of the meandering river channel could have brought in the difficulties for applying simple spatial interpolation methods for handling dynamic flow velocity vector, since the flow direction continuously changes over the curvature of the channel shape. Without considering anisotropic characteristics in terms of the meandering, therefore, conventional interpolation methods such as IDW and Kriging possibly lead to erroneous results, when they dealt with velocity vectors in the meandering channel. Based on the consecutive ADCP cross-sectional measurements in the meandering river channel. For this purpose, the geographic coordinate with the measured ADCP velocity was converted from the conventional Cartesian coordinate (x, y) to a curvilinear coordinate (s, n). The results from application of A-VIM showed significant improvement in accuracy as much as 41.5% in RMSE.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.24 no.2
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• pp.351-373
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• 2019

The cold eddies around the Ulleung Basin in the East Sea were identified from satellite altimeter sea level data using the Winding-Angle method from 1993 to 2015. Among the cold eddies, the Dokdo Cold Eddies (DCEs), which were formed at the first meandering trough of the East Korea Warm Current (EKWC) and were pinched off to the southwest from the eastward flow, were classified and their migration patterns were analyzed. The vertical structures of water temperature, salinity, and flow velocity near the DCE center were also examined using numerical simulation and observation data provided by the Hybrid Coordinate Ocean Model and the National Institute of Fisheries Science, respectively. A total of 112 DCEs were generated for 23 years. Of these, 39 DCEs migrated westward and arrived off the east coast of Korea. The average travel distance was 250.9 km, the average lifespan was 93 days, and the average travel speed was 3.5 cm/s. The other 73 DCEs had moved to the east or had hovered around the generated location until they disappeared. At 50-100 m depth under the DCE, water temperature and salinity (T < $5^{\circ}C$, S < 34.1) were lower than those of ambient water and isotherms made a dome shape. Current faster than 10 cm/s circulates counterclockwise from the surface to 300 m depth at 38 km away from the center of DCE. After the EKWC separates from the coast, it flows eastward and starts to meander near Ulleungdo. The first trough of the meander in the east of Ulleungdo is pushed deep into the southwest and forms a cold eddy (DCE), which is shed from the meander in the south of Ulleungdo. While a DCE moves westward, it circumvents the Ulleung Warm Eddy (UWE) clockwise and follows U shape path toward the east coast of Korea. When the DCE arrives near the coast, the EKWC separates from the coast at the south of DCE and circumvents the DCE. As the DCE near the coast weakens and extinguishes about 30 days later after the arrival, the EKWC flows northward along the coast recovering its original path. The DCE steadily transports heat and salt from the north to the south, which helps to form a cold water region in the southwest of the Ulleung Basin and brings positive vorticity to change the separation latitude and path of the EKWC. Some of the DCEs moving to the west were merged into a coastal cold eddy to form a wide cold water region in the west of Ulleung Basin and to create a elongated anticlockwise circulation, which separated the UWE in the north from the EKWC in the south.