• 한국농공학회지
• /
• 제41권1호
• /
• pp.39-51
• /
• 1999

This study has an object to evaluate runoff characteristics with ILLUDAS model and SWMM owing to each rainfall distribution type of Huff's quartile and each rainfall duration time of 30 ,60, 120 and 180 minutes. As a result of this study, Type-Ⅰ Extreme (TIE) rainfall distribution pattern with Huff's 2nd quartile is adequate for Cheju volcanic island . To decide optimal rain fall duration , time of concentration and critical duration should be compared and analyzed each other. In this study, 30 and 120 miniutes were suggeste to iptiaml duration time of A and B study basins. It is concluded that the magnitude of peak runoff discharge is maximum with Huff's 4th quartile, and that of total runoff volume is maximum with Huff's 4th quartile for ILLUDAS model and with Huff's 1st quartile for SWMM. As rainfall duration time increasing is increasing . Also in case of total runoff volume, volumen by SWMM is less than by ILLUDAS model as to variation ratio of total runoff volume in A and B study basin. Therefore, the resulots of this study canb e sued as basic data in determining adequate rainfoal duration time and rainfall distribution type and used for urban drainage systems analysis and design at small urbanization catchment is Cheju volcanic island.

• 한국농공학회지
• /
• 제36권1호
• /
• pp.141-152
• /
• 1994

Our experiment investigated the degree of soil contaimination caused by oil leakage. Each soil sample was taken by boring 5, 8m below the test areas, located 5 to 30m from storage tanks at oil stations. According to the results from a series of laboratory tests(both soxhiet extract test and gas chromatograph test), Traces of a light oil were found in all samples except in Dj8, rocky soil and gasoline and petroleum were not detected. We concluded that soil contamination was caused by the corrosion of storage tanks or alternatively by oil overflow caused during the flooding of underground water seeping into the tank during heavy rain fall or the spillage caused by carelessness during lubrication. Old stations without a concrete box enclosing their metal tanks run a greater risk of oil leakage. To research the effect of oil leakage on plant growth and underground water, We examined the results of research conducted overseas. According to these results, when oil leakage occurs, plant growth is repressed and agricultural crops experience low productivity levels. Also, the contamination of underground water can be serious when oil spreads to the aquifer layer. As a result of these problems, to prevent oil leakage and minimize its contaminating effects at oil stations, it is necessary to improve facilities of storage tanks and have the monitoring system of oil leakage.

• 대한안전경영과학회지
• /
• 제11권1호
• /
• pp.1-6
• /
• 2009

The specific feature of trains as a means of transportation is that, on one side, at once they can carry big loads but, at the same time, if an accident occurs, it potentially leads to many human casualties or big material losses. Especially, train accidents caused by bad weather conditions result in many fatal losses of human lives and property. In Korea many railways run either in mountainous areas or along rivers thus making them especially susceptible to natural hazards. The types of damages inflicted by heavy rains resulting from rapidly changing meteorological conditions are diverse; and not only their scope is big but also they repeat regularly. Consequently, this study analyses the reasons why such effects of heavy rains on the railway conditions, damage to the railways caused by heavy rains or cases of stone fall as well as other types of accidents are not avoided. Study also, on the basis of laws related to movement in poor weather conditions and specifics of train braking, identifies systematic and technical problems and suggests and emphasizes new complex measures on their prevention.

• 한국통신학회논문지
• /
• 제24권9B호
• /
• pp.1608-1615
• /
• 1999

본 연구에서는 LMDS 시스템의 설계시 셀 내부에서 발생할 수 있는 간섭을 분석하였다. 셀 내부에서 발생할 수 있는 간섭은 크게 동일 편파 인접 채널 간섭, 교차 편파 간섭, 송수신 채널간의 간섭이 있을 수 있으며, 본 연구에서는 각각에 대한 분석 결과를 종합하여 셀 내부의 간섭 조건을 분석하였다. 이러한 각각의 간섭을 종합한 결과 강우 감쇄를 고려한 상황에서 C/N은 2 km 구간까지 19 dB 이상을 유지하지만, 그 이상의 구간에서는 급격히 떨어짐을 알 수 있었다. 따라서 LMDS 시스템의 셀 반경은 2 km가 적절하다고 판단되었다. 본 논문에서는 이러한 분석결과에 근거하여 실험을 진행하였으며 이론적인 결과와 마찬가지로 C/I=20 dB 이상을 만족하여야만 강우감쇄 상황에서도 정상적인 수신이 가능함을 알 수 있었다.

• 한국지반환경공학회 논문집
• /
• 제23권4호
• /
• pp.41-48
• /
• 2022

제주도는 지질학적 특성으로 인해 '숨골'이라는 특수한 형태의 지층이 존재한다. 숨골은 대량의 물이 막힘없이 지하로 침투하는 지질구조로서, 동굴과 달리 사람이 들어가지 못하는 곳으로 정의된다. 본 논문은 이러한 숨골이 존재하는 지역의 시추조사 결과를 바탕으로 공항 건설시 발생하는 다양한 하중에 대하여 지반의 안정성을 수치해석을 통하여 살펴보았다. 숨골의 영향범위를 지표에서 3m로 설정하여 수치해석을 수행한 결과 표층에 매립지가 존재하는 지역을 포함하여 모든 단면에서 허용 침하량 범위에 있었다. 또한 매립지가 존재하는 단면의 경우 실제 포장건설 시를 고려하여 수치해석을 수행한 결과 침하량은 매우 줄어드는 것을 알 수 있었다.

• 국제학술발표논문집
• /
• The 6th International Conference on Construction Engineering and Project Management
• /
• pp.678-679
• /
• 2015

Recently, safety accidents in construction sites are increasing. Accordingly, in this study, development of 'Big-Data Analysis Modeling' can collect articles from last 10 years which came from the Internet News and draw the cause of accidents that happening per season. In order to apply this study, Web Crawling Modeling that can collect 98% of desired information from the internet by using 'Xml', 'tm', "Rcurl' from the library of R, a statistical analysis program has been developed, and Datamining Model, which can draw useful information by using 'Principal Component Analysis' on the result of Work Frequency of 'Textmining.' Through Web Crawling Modeling, 7,384 out of 7,534 Internet News articles that have been posted from the past 10 years regarding "safety Accidents in construction sites", and recognized the characteristics of safety accidents that happening per season. The result showed that accidents caused by abnormal temperature and localized heavy rain, occurred frequently in spring and winter, and accidents caused by violation of safety regulations and breakdown of structures occurred frequently in spring and fall. Plus, the fact that accidents happening from collision of heavy equipment happens constantly every season was acknowledgeable. The result, which has been obtained from "Big-Data Analysis Modeling" corresponds with prior studies. Thus, the study is reliable and able to be applied to not only construction sites but also in the overall industry.

• 한국환경농학회지
• /
• 제42권4호
• /
• pp.311-323
• /
• 2023

Miscanthus sinensis Andersson (Poaceae) cultivars exhibit excellent visual appeal as ornamental grasses and adapt well to diverse environmental conditions. This study focused on assessing the growth response and landscape durability of seven popular Miscanthus cultivars ('Gold Breeze', 'Strictus', 'Morning Light', 'Variegatus', 'Gracillimus', 'Kleine Fontäne', 'Common') under drought, rainfall and low temperature condition. The test cultivars were transplanted and cultivated on research plots in 2013, with data collected from June 2017 to February 2018. Plant materials were categorized into three types based on the amount of the water lost; group I ('Kleine Fontäne', 'Variegatus', 'Strictus'), experiencing the most significant water loss; group II ('Common', 'Gracillimus'); and group III ('Gold Breeze', 'Morning Light') where the least water loss occurred. The drought resistance index (DRI) remained low as water shortage conditions persisted. The lodged angle underwent more pronounced changes in reproductive growth stage than in vegetative growth stage, notably decreasing after heading. Discoloration patterns were classified into two types: group I ('Common', 'Gold Breeze', 'Kleine Fontäne', 'Strictus') and group II ('Gracillimus', 'Morning Light', 'Variegatus') based on the periods of peak duration.

• 농업생명과학연구
• /
• 제46권3호
• /
• pp.1-10
• /
• 2012

본 연구는 대기오염으로 인한 $SO_2$와 $NO_2$ 그리고 산성비 등의 건성 및 습성강하물의 영향을 받고 있는 공단지역 주변 산림과 대조지역의 해송림에서 해송림의 쇠퇴도 사이에 상관분석과 단계적 회귀분석을 통하여 해송 잎의 쇠퇴와 엽록소 함량에 가장 영향을 미치는 인자를 구명하였다. 수관통과우의 pH는 도시공단지역이 봄철 4.65, 가을철 4.72이었고, 대조지역이 봄철 5.32과 가을철 5.34였다. 음이온 성분 중에서 ${NO_3}^-$의 농도는 도시공단지역이 $52.13mg/{\ell}$ 대조지역은 $37.85mg/{\ell}$이었다. ${SO_4}^{2-}$ 함량은 도시공단지역이 $57.89mg/{\ell}$, 대조지역이 $36.21mg/{\ell}$이었다. $Ca^{2+}$의 농도는 도시공단지역이 $27.27mg/{\ell}$, 대조지역이 $9.48mg/{\ell}$ 이었다. 해송 잎의 엽록소 a의 함량은 도시공단지역이 0.2378이었고, 대조지역은 0.4378이었다. 해송의 쇠퇴도는 도시공단지역 2.97, 대조지역 1.20이었다. 해송 임분의 쇠퇴도와 강우의 이온성분, $SO_2$, $NO_2$ 농도와 상관분석 결과에서 강우산도 상호간에는 부의 상관(r=-0.8672)이었고, 대기 중 $SO_2$ 농도는 정의 상관(r=0.8924)이었으며, $NO_2$ 농도도 정의 상관(r=0.8428)이었다. 이러한 산성강하물 상호간의 상관관계는 pH(r=-0.8672), ${NO_3}^-$(r=0.6996), ${SO_4}^{2-}$(r=0.8497), $SO_2$ (r=0.8924), $NO_2$(r=0.8428)는 1% 수준에서 상관이 있었다.

• 대기
• /
• 제24권2호
• /
• pp.173-188
• /
• 2014

The KMA has cooperated with the Oklahoma University in USA to develop a Polarimetric Radar Data (PRD) simulator to improve the microphysical processes in Korea Local Analysis and Prediction System (KLAPS), which is critical for the utilization of PRD into Numerical Weather Prediction (NWP) field. The simulator is like a tool to convert NWP data into PRD, so it enables us to compare NWP data with PRD directly. The simulator can simulate polarimetric radar variables such as reflectivity (Z), differential reflectivity ($Z_{DR}$), specific differential phase ($K_{DP}$), and cross-correlation coefficient (${\rho}_{hv}$) with input of the Drop Size Distribution (DSD) and scattering calculation of the hydrometeors. However, the simulator is being developed based on the foreign observation data, therefore the PRD simulator development reflecting rainfall characteristics of Korea is needed. This study analyzed a potential application of the 2-Dimension Video Disdrometer (2DVD) data by calculating the raindrop axis ratio according to the rain-types to reflect Korea's rainfall characteristics into scattering module in the simulator. The 2DVD instrument measures the precipitation DSD including the fall velocity and the shape of individual raindrops. We calculated raindrop axis ratio for stratiform, convective and mixed rainfall cases after checking the accuracy of 2DVD data, which usually represent the scattering characteristics of precipitation. The raindrop axis ratio obtained from 2DVD data are compared with those from foreign database in the simulator. The calculated the dual-polarimetric radar variables from the simulator using the obtained raindrop axis ratio are also compared with in situ dual-polarimetric observation data at Bislsan (BSL). 2DVD observation data show high accuracies in the range of 0.7~4.8% compared with in situ rain gauge data which represents 2DVD data are sufficient for the use to simulator. There are small differences of axis ratio in the diameter below 1~2 mm and above 4~5 mm, which are more obvious for bigger raindrops especially for a strong convective rainfall case. These differences of raindrop axis ratio between domestic and foreign rainfall data base suggest that the potential use of disdrometer observation can develop of a PRD simulated suitable to the Korea precipitation system.

• 대기
• /
• 제34권3호
• /
• pp.305-317
• /
• 2024

The study examines the effects of parameters that define the characteristics of raindrops on the simulated precipitation during the summer season over Korea using the Weather Research and Forecasting (WRF) Double-Moment 6-class (WDM6) cloud microphysics scheme. Prescribed parameters, defining the characteristics of hydrometeors in the WDM6 scheme such as a_R, b_R, and f_R in the fall velocity (V_R) - diameter (D_R) relationship and shape parameter (𝜇_R) in the number concentration (N_R) - D_R relationship, presents different values compared to the observed data from Two-Dimensional Video Disdrometer (2DVD) at Boseong standard meteorological observatory during 2018~2019. Three experiments were designed for the heavy rainfall event on August 8, 2022 using WRF version 4.3. These include the control (CNTL) experiment with original parameters in the WDM6 scheme; the MUR experiment, adopting the 50th percentile observation value for 𝜇_R; and the MEDI experiment, which uses the same 𝜇_R as MUR, but also includes fitted values for a_R, b_R, and f_R from the 50th percentile of the observed V_R - D_R relationship. Both sensitivity experiments show improved precipitation simulation compared to the CNTL by reducing the bias and increasing the probability of detection and equitable threat scores. In these experiments, the raindrop mixing ratio increases and its number concentration decreases in the lower atmosphere. The microphysics budget analysis shows that the increase in the rain mixing ratio is due to enhanced source processes such as graupel melting, vapor condensation, and accretion between cloud water and rain. Our study also emphasizes that applying the solely observed 𝜇_R produces more positive impact in the precipitation simulation.