유역물수지모형을 이용한 일별 유출량 모의

김학관,박승우,황세운,장태일 한국수자원학회 2005 한국수자원학회 학술대회 Vol.2005 No.1

생체재료의 선택에 따른 조골세포의 형상, 증식 및 분화

김학관,장주웅,정희석,이득용 한국세라믹학회 2003 한국세라믹학회지 Vol.40 No.6

재료의 선택에 따른 생체친화성을 고찰하기 위해서 조골세포의 세포배양실험을 실시하였으며, 이로부터 세포의 부착형상, 증식, 분화의 정도를 살펴보았다. 본 실험에서 세포배양모재는 체내식립재료로 주목을 받고 있는 TiO$_2$, 3Y-TZP, HA (Hydroxyapatite) 그리고 Ti를 사용하였으며 대조군으로 Thermanox를 선택하였다. 일반적으로 모든 시편들은 같은 세포배양시간일때 거의 유사한 세포부착형상을 보였다. 그러나, HA위의 세포들은 나머지 시편들보다 좀 더 두꺼운 형상을 보였으며 빠른 세포의 부착 및 퍼짐으로 인한 overlapping이 자주 관찰되었다. 세포의 증식 및 분화의 경우에도 생체활성의 특성을 지니는 HA가 가장 높은 값을 보였으며 생체불활성재료인 경우에는 Ti, TiO$_2$, 3Y-TZP모두 유의한 차이를 보이지 않고 비슷한 경향을 나타내었다. Osteoblast-like cell morphology, proliferation, and differentiation were examined in variation with biomaterials. Cells were cultured on TiO$_2$, Ti, 3Y-TZP, HA (Hydroxyapatite) and Thermanox was used as a control specimen. Generally, all specimens have similar cell morphology within the same time interval. However, cells on HA seem to be more thicker than those on TiO$_2$, Ti, 3Y-TZP and cell overlapping was detected very frequently on HA. In case of cell proliferation and differentiation, bioactive material such as HA could help osteoblast-like cell proliferate and provoke a sharp increase of ALP. On the other hand, whether the substrate material is a bioinert ceramics or metal, it does not so strongly affect the cell attachment, proliferation. and differentiation.

강우유출수 관리시설의 설계를 위한 강우사상 특성 분석

김학관,지현서,장선숙,Kim, Hak Kwan,Ji, Hyun Seo,Jang, Sun Sook 한국농공학회 2017 한국농공학회논문집 Vol.59 No.6

The objective of this study is to investigate whether the daily rainfall depth derived from daily data represents the event rainfall depth derived from hourly data. For analysis, the 85th, 90th, and 95th percentile daily rainfall depths were first computed using daily rainfall data (1986~2015) collected at 63 weather stations. In addition, the storm event was separated by the interevent time definition (IETD) of 6, 12, 18, and 24 hr using hourly rainfall data. Based on the separated storm events, the 85th, 90th, and 95th percentile event rainfall depths were calculated and compared with the using hourly rainfall data with the 85th, 90th, and 95th percentile daily rainfall depths. The event rainfall depths computed using the IETD were greater than the daily rainfall depths. The difference between the event rainfall depth and the daily rainfall depth affects the design and size of the facility for controlling the stormwater. Therefore, the designer and policy decision-maker in designing the stormwater best management practices need to take into account the difference generated by the difference of the used rainfall data and the selected IETD.

다중목적 최적화기 법을 이용한 SWAT 모형 수분매개변수의 자동보정

김학관,강문성,박승우,최지용,양희정,Kim, Hak-Kwan,Kang, Moon-Seong,Park, Seung-Woo,Choi, Ji-Yong,Yang, Hee-Jeong 한국농공학회 2009 한국농공학회논문집 Vol.51 No.1

The objective of this paper was to evaluate the auto-calibration with multi-objective optimization method to calibrate the parameters of the Soil and Water Assessment Tool (SWAT) model. The model was calibrated and validated by using nine years (1996-2004) of measured data for the 384-ha Baran reservoir subwatershed located in central Korea. Multi-objective optimization was performed for sixteen parameters related to runoff. The parameters were modified by the replacement or addition of an absolute change. The root mean square error (RMSE), relative mean absolute error (RMAE), Nash-Sutcliffe efficiency index (EI), determination coefficient ($R^2$) were used to evaluate the results of calibration and validation. The statistics of RMSE, RMAE, EI, and $R^2$ were 4.66 mm/day, 0.53 mm/day 0.86, and 0.89 for the calibration period and 3.98 mm/day, 0.51 mm/day, 0.83, and 0.84 for the validation period respectively. The statistical parameters indicated that the model provided a reasonable estimation of the runoff at the study watershed. This result was illustrated with a multi-objective optimization for the flow at an observation site within the Baran reservoir watershed.

농경지 불투수면 변화에 따른 유역 수문 영향 분석

김학관,이은정,박승우,강문성,Kim, Hak-Kwan,Lee, Eun-Jeong,Park, Seung-Woo,Kang, Moon-Seong 한국농공학회 2009 한국농공학회논문집 Vol.51 No.6

The Soil and Water Assessment Tool (SWAT) model was used in this study to evaluate the hydrologic impacts by the impervious surface change in the farm region. The model was calibrated and validated by using four years (1999-2002) of measured data for the Gyeongancheon watershed in Korea. The simulation results agreed well with observed values during the calibration and validation periods. Land use scenarios including various changes of the plastic film house area in the farm region were applied to assess their effects on watershed hydrology. The results indicated that the surface direct (5.6%~14.0%) and total runoff (0.8%~1.5%) increased, but the groundwater discharge (10.7%~27.7%) and evapotranspiration (1.5%~3.3%) decreased as the plastic film house area (5.7%~12.4%) increased.

하천에서의 영양물질 관리를 위한 총질소 환경기준 설정에 관한 연구

김학관,정한석,배승종,Kim, Hak Kwan,Jeong, Han,Bae, Seung Jong 한국농공학회 2015 한국농공학회논문집 Vol.57 No.3

The objective of this study is to suggest the water quality criteria of total nitrogen in order to efficiently manage the nutrient pollution in the stream. For this, correlations between water quality parameters were examined using the water quality data collected from the water quality monitoring network in the four rivers between 2003 and 2012. T-N showed positive correlations with T-P (0.636), COD (0.577), BOD (0.574), TOC (0.440), and SS (0.367). The statistical analysis including percentile analysis for the T-N and T-P concentrations was utilized to develop the water quality criteria of T-N. The feasibility of the suggested water quality criteria was evaluated by calculating the achievement rate to water quality target at the representative points in mid-watershed, then the draft water quality standard of T-N was suggested. The suggested water quality standard of T-N in the stream may be used to efficiently control the nutrient pollution in the public water body.

장래 기후변화와 토지이용 변화에 따른 농촌소유역의 수문 영향 분석

김학관,강문성,이은정,박승우,Kim, Hak-Kwan,Kang, Moon-Seong,Lee, Eun-Jeong,Park, Seung-Woo 한국농공학회 2011 한국농공학회논문집 Vol.53 No.6

The objective of this study is to evaluate the hydrologic impacts of climate and land use changes in a rural small watershed. HadCM3 (Hadley Centre Coupled Model, ver.3) A2 scenario and LARS-WG (Long Ashton Research Station - Weather Generator) were used to generate future climatic data. Future land use data were also generated by the CA-Markov (Cellular Automata-Markov) method. The Soil and Water Assessment Tool (SWAT) model was used to evaluate hydrologic impacts. The SWAT model was calibrated and validated with stream flow measured at the Baran watershed in Korea. The SWAT model simulation results agreed well with observed values during the calibration and validation periods. In this study, hydrologic impacts were analyzed according to three scenarios: future climate change (Scenario I), future land use change (Scenario II), and both future climate and land use changes (Scenario III). For Scenario I, the comparison results between a 30-year baseline period (1997~2004) and a future 30-year period (2011~2040) indicated that the total runoff, surface runoff, lateral subsurface runoff, groundwater discharge, and evapotranspiration increased as precipitation and temperature for the future 30-year period increased. The monthly variation analysis results showed that the monthly runoff for all months except September increased compared to the baseline period. For Scenario II, both the total and surface runoff increased as the built-up area, including the impervious surface, increased, while the groundwater discharge and evapotranspiration decreased. The monthly variation analysis results indicated that the total runoff increased in the summer season, when the precipitation was concentrated. In Scenario III, the results showed a similar trend to that of Scenario II. The monthly runoff for all months except October increased compared to the baseline period.

SWAT과 HSPF 모형을 이용한 유출특성 비교분석

김학관,김상민,박승우 한국수자원학회 2004 한국수자원학회 학술대회 Vol.2004 No.1

2013년 축종별 배합사료산업 전망 - 양돈 사료산업 전망

김학관,Kim, Hak-Gwan 한국사료협회 2012 飼料 Vol.59 No.-

HEC-HMS와 HEC-RAS를 이용한 농촌 저지대 침수해석

김학관,강문성,송인홍,황순호,박지훈,송정헌,김지혜,Kim, Hak-Kwan,Kang, Moon-Seong,Song, In-Hong,Hwang, Soon-Ho,Park, Ji-Hoon,Song, Jung-Hun,Kim, Ji-Hye 한국농공학회 2012 한국농공학회논문집 Vol.54 No.2

The objective of this study is to analyze the flood inundation in a low-lying rural area. The study watershed selected for this study includes the Il-Pae and Ahn-Gok watersheds. It is located in the Namyangju, Korea and encompasses $3.64km^2$. A major flood event that occurred in July 2011 was chosen as the case for the flood inundation analysis. The Hydrologic Engineering Center's Hydrologic Modeling System (HEC-HMS) and River Analysis System (HEC-RAS) were used to simulate flood runoff and water surface elevation at each cross-section, respectively. The watershed topographic, soil, and land use data were processed using the GIS (Geographic Information System) tool for the models. The contribution to the total flood volume was estimated based on the results simulated by HEC-HMS and HEC-RAS. The results showed that the overflow discharge from the Il-Pae stream constituted 80% of the total flood volume. The contributions of rainfall falling directly on the inundation area and overflow discharge from the Ahn-Gok stream were 15 % and 5 %, respectively. The simulation results in different levee scenarios for the Ahn-Gok stream were also compared. The results indicated that the levee could reduce the flood volume a little bit.