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Assessment of Hydrological Impact by Long-Term Land Cover Change using WMS HEC-1 Model in Gyeongan-cheon Watershed (WMS HEC-1 모형을 이용한 경안천 유역의 경년 수문변화 분석)

  • Lee, Jun-Woo;Kwon, Hyung-Joong;Shin, Sha-Chul;Kim, Seong-Joon
    • Journal of the Korean Association of Geographic Information Studies
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    • v.6 no.1
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    • pp.107-118
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    • 2003
  • The purpose of this study is to assess the hydrological impact on a watershed from long-term land cover changes. Gyeongan-cheon watershed($558.2km^2$) was selected and WMS(watershed modeling system) HEC-1 model was adopted as an evaluation tool. To identify land cover changes, five Landsat images(1980/2/15, 1986/4/15, 1990/4/26, 1996/4/26, 2000/5/17) were selected and analyzed using maximum likelihood method. As a result, urban areas have increased by 5.6% and forest areas have decreased by 6.1% between 1980 and 2000. SCS curve number increased by 9.8. To determine model parameters and evaluate HEC-1 model, five storm events(1998/5/2, 1998/8/23, 1998/9/30, 1999/5/3, 2000/7/29) were used. The simulated stream flow agreed well with the observed one with relative errors ranging from 9% to 36%. For 254 mm daily rainfall of 30 years frequency, due to the increase of urban areas peak flow increased by $455m^3/sec$ and the time of peak flow reduced about four hours for 20 years land cover changes.

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Studies on the Disease Development and Chemical Control of Tobacco Wild Fire (담배 야화병의 발생소장과 그 방제에 관한 연구)

  • Hou Il;Ban Yoo Sun
    • Korean journal of applied entomology
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    • v.9 no.2
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    • pp.91-94
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    • 1970
  • Tobacco wild fire caused by Pseudomonas tabaci(Wolf et Foster) Stevens is one of the most important diseases on tobacco plant in Korea. The objectives of the study were to investigate: 1) the relationships between environmental conditions and the disease development, 2) the effect of chemical spray and soil sterilization on the disease development, and 3) the proper date for chemical sprays during the growing season. The appearance of wild fire on tobacco plant was somewhat proportional to temperature and moisture in atmosphere. The first occurrence of the disease was in late part of June when the temperature was $18\;to\;20^{\circ}C$. with $65\;to\;70^{\circ}C$ of relative humidity. The disease was, then, gradually increased during early part of July with the temperature of $22\;to\;26^{\circ}C$. and $85\;to\;86^{\circ}C$ of. relative humidity. The rapid development of the disease occurred after heavy rain or storm during July. Two to three times of Phytomycin sprays(1:300-350) during the epidemic season reduced $28.3\%$ of disease damage when compared with control plot. Soil sterilization with chloropicrin. 10 liter/10a, Prior to transplanting of seedlings reduced not only wild fro damage but also the other tobacco diseases on field. The study showed that the damage caused by tobacco wild fro could be reduced with the use of early varieties and/or 2 or 3 times of Phytomycin sprays during early part of June, and soil sterilization with chloropicrin prior to transplanting.

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Immunomodulatory effect of mesenchymal stem cells and mesenchymal stem-cell-derived exosomes for COVID-19 treatment

  • Jayaramayya, Kaavya;Mahalaxmi, Iyer;Subramaniam, Mohana Devi;Raj, Neethu;Dayem, Ahmed Abdal;Lim, Kyung Min;Kim, Se Jong;An, Jong Yub;Lee, Yoonjoo;Choi, Yujin;Kirubhakaran, Arthi;Cho, Ssang-Goo;Vellingiri, Balachandar
    • BMB Reports
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    • v.53 no.8
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    • pp.400-412
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    • 2020
  • The world has witnessed unimaginable damage from the coronavirus disease-19 (COVID-19) pandemic. Because the pandemic is growing rapidly, it is important to consider diverse treatment options to effectively treat people worldwide. Since the immune system is at the hub of the infection, it is essential to regulate the dynamic balance in order to prevent the overexaggerated immune responses that subsequently result in multiorgan damage. The use of stem cells as treatment options has gained tremendous momentum in the past decade. The revolutionary measures in science have brought to the world mesenchymal stem cells (MSCs) and MSC-derived exosomes (MSC-Exo) as therapeutic opportunities for various diseases. The MSCs and MSC-Exos have immunomodulatory functions; they can be used as therapy to strike a balance in the immune cells of patients with COVID-19. In this review, we discuss the basics of the cytokine storm in COVID-19, MSCs, and MSC-derived exosomes and the potential and stem-cell-based ongoing clinical trials for COVID-19.

Sediment Transport Characteristics in a Pressure Pipeline (압력 원형관로내 유사이송특성 연구)

  • Son, Kwang Ik;Kim, Hyun Jung
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.31 no.3B
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    • pp.205-209
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    • 2011
  • The low carrying capacity caused by the deposition in a sewer line is one of the main reason of the urban flood. Therefore, an efficient maintenance and management of the storm water drainage system is very important to prevent urban flood. In this research, the sediment transport characteristics through a pressure pipeline were examined with laboratory experiments. Bed-forms in a pipeline, sediment rates, roughness due to sediments were examined. Experimental system consists of flow circulation system with a pump and a sediment feeder at the upstream of the pipeline. Sediments were supplied into a 60 mm-diameter and 8 m-long pipe. Maximum flow rate is $30m^3/hr$, and the sediment feeding rate range is 5 g/s~19 g/s. Governing parameters and estimation equation for sediment transport rate were developed. The mean velocity (U), coefficient of viscosity (${\mu}$), unit width bed load ($q_b$), mean diameter of particle ($d_{50}$), unit weight of sediment in water (${\gamma}^{\prime}_s$) were adopted as the most influencing factors of sediment transport patterns. The prediction equation for sediment transport rate were developed with two dimensionless terms. These two dimensionless terms showed a linear relationship with high correlation coefficient.

Predicting Long-Term Shoreline Change Due to the Construction of Submerged Breakwaters in Manseongri Beach (잠제설치에 따른 만성리해빈에서 해안선의 장기변화 예측)

  • Park, Il Heum;Kang, Seong Wuk;Kang, Tae-Soon
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.22 no.5
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    • pp.527-535
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    • 2016
  • The Manseongri Coast meets the sea on the southeast and is composed of coarse sediment as a mesotidal beach. The waves that strike the beach are stronger than the tides or tidal currents as external forces of beach deformation. Storm waves frequently reach significant wave heights of 2-3m and hit in spring and summer, leaving the sea calm during fall and winter. Incident waves reach remarkable heights that correspond with observed shoreline changes. The shoreline erodes in spring and summer due to these strong waves but recovers in fall and winter as a result of the more moderate waves. On the basis of these observed results, a numerical calibration for experiments on shoreline change was established. Results revealed that according to hindcast data, calculated shoreline changes agreed with the observed shoreline, with a minimum RMS error of 1.26m with calibration parameters $C_1=0.2$ and $C_2=1C_1$. Using these calibration parameters, long-term shoreline change was predicted after the construction of submerged breakwaters and jetties, etc. The numerical model showed that the shoreline would move forward by 5-15m behind the submerged breakwaters and recede by 5-15m north of the structure.

Research of Runoff Management in Urban Area using Genetic Algorithm (유전자알고리즘을 이용한 도시화 유역에서의 유출 관리 방안 연구)

  • Lee, Beum-Hee
    • Journal of the Korean Geophysical Society
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    • v.9 no.4
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    • pp.321-331
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    • 2006
  • Recently, runoff characteristics of urban area are changing because of the increase of impervious area by rapidly increasing of population and industrialization, urbanization. It needs to extract the accurate topologic and hydrologic parameters of watershed in order to manage water resource efficiently. Thus, this study developed more precise input data and more improved parameter estimating procedures using GIS(Geographic Information System) and GA(Genetic Algorithm). For these purposes, XP-SWMM (EXPert-Storm Water Management Model) was used to simulate the urban runoff. The model was applied to An-Yang stream basin that is a typical Korean urban stream basin with several tributaries. The rules for parameter estimation were composed and applied based on quantity parameters that are investigated through the sensitivity analysis. GA algorithm is composed of these rules and facts. The conditions of urban flows are simulated using the rainfall-runoff data of the study area. The data of area, slope, width of each subcatchment and length, slope of each stream reach were acquired from topographic maps, and imperviousness rate, land use types, infiltration capacities of each subcatchment from land use maps, soil maps using GIS. Also we gave the management scheme of urbanization runoff using XP-SWMM. The parameters are estimated by GA from sensitivity analysis which is performed to analyze the runoff parameters.

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Identifying Cost and Benefit Items of Investment Projects to Offer New Public Services By the Use of Food Waste Disposers and the Direct Input of Feces in Sewers (주방오물분쇄기 사용 및 수세분뇨의 직투입에 따른 「새로운 공공하수도 서비스」제공을 위한 투자사업의 비용과 편익 항목 식별)

  • Oh, Hyun-Taek;Park, Kyoo-Hong;Kim, Sung Tai;Lim, Byung In
    • Journal of Convergence for Information Technology
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    • v.10 no.5
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    • pp.117-125
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    • 2020
  • Our study identifies a cost and a benefit incurred in implementing an investment project to offer new public services by use of food waste disposers and direct input of feces in sewers. This is done with identifying costs of each processing division and benefits of the project by objective statistical data and engineering perspective. In summary, cost items identified are as follows: there are house laterals, removal of septic tanks, etc. for sewer pipes system. As to water quality conservation, cost incurs in storm water outfalls and divert chambers, sewage storage tanks, equipment to treat sewer overflows, and so on. With respect to sewage treatment plants(STPs), there are so many items as increase of contaminant loads in influent of STPs, and other items. There are benefit items in health improvement due to odor mitigation, increase of energy productivity, saving cost of food waste treatment and cleaning septic tanks, etc. These estimates will be used as a basic data for its economic effect.

A Study on Blasting Method for the Smallest of the Scour Depth after Pier Construction (교각의 세굴심도 최소화를 위한 발파공법 연구)

  • 김가현;김종주;안명석
    • Explosives and Blasting
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    • v.21 no.3
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    • pp.23-35
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    • 2003
  • An analytical diffusion model for flood routing with backwater effects and lateral flows is developed. The basic diffusion equation is linearized about an average depth of (H + h), and is solved using the boundary conditons which take into account the effects of backwater and lateral flows. Scouring phenomenon around pier which affects on the support function of pier and the stabilization if river bed is a complex problem depending on flow properties and river bed state as well as pier geometry. therefore, there is no uniting theory at present which would enable the designer to estimate, with confidence, the depth of scour at bridge piers. The various methods used in erosion control are collectively called upstream engineering, HEC-RAS Model, underwater blasting. They consist of reforestation, check-dam construction, planting of burned-over areas, contour plowing and regulation of crop and grazing practices. Also included are measures for proper treatment of high embankments and cuts and stabilization of streambanks by planting or by revetment construction. One phase of reforestation that may be applied near a reservoir is planting of vegetation screens. Such screens, planted on the flats adjacent to the normal stream channel at the head of a reservoir, reduce the velocity of silt-laden storm inflows that inundate these areas. This stilling action causes extensive deposition to occur before the silt reaches the main cavity of the reservoir.

Evaluation of Sediment Yield Prediction and Estimation of Sediment Yield under Various Slope Scenarios at Jawoon-ri using WEPP Watershed Model (WEPP Watershed Version을 이용한 홍천군 자운리 농경지 토양유실 예측 및 경사도에 따른 토양유실량 평가)

  • Choi, Jaewan;Hyun, Geunwoo;Lee, Jae Woon;Shin, Dong Suk;Kim, Ki-Sung;Park, Younshik;Kim, Jonggun;Lim, Kyoung Jae
    • Journal of Korean Society on Water Environment
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    • v.25 no.3
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    • pp.441-451
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    • 2009
  • To evaluate the soil erosion best management practices, many computer models has been utilized over the years. Among those, the USLE and SWAT models have been widely used. These models estimate the soil erosion from the field using empirically-based USLE/MULSE in it. However, these models are not good enough to estimate soil erosion from highland agricultural watershed where severe storm events are causing soil erosion and muddy water issues at the receiving watersheds. Thus, physically-based WEPP watershed version was applied to a watershed, located at Jawoon-ri, Gangwon with very detailed rainfall data, rather than daily rainfall data. Then it was validated with measured sediment data collected at the sediment settling ponds and through overland flow. In this study, very detailed rainfall data, crop management data, soil data reflecting soil reconditioned for higher crop production were used in the WEPP runs. The $R^2$ and the EI for runoff comparisons were 0.88 and 0.91, respectively. For sediment comparisons, the $R^2$ and the EI values were 0.95 and 0.91. Since the WEPP provides higher accuracies in predicting runoff and sediment yield from the study watershed, various slope scenarios (2%, 3%, 5.5%, 8%, 10%, 13%, 15%, 18%, 20%, 23%, 25%, 28%, 30%) were made and simulated sediment yield values were analyzed to develop appropriate soil erosion management practices. It was found that soil erosion increase linearly with increase in slope of the field in the watershed. However, the soil erosion increases dramatically with the slope of 20% or greater. Therefore special care should be taken for the agricultural field with slope greater than 20%. As shown in this study, the WEPP watershed version is suitable model to predict soil erosion where torrential rainfall events are causing significant amount of soil loss from the field and it can also be used to develop site-specific best management practices.

Lithofacies and Stable Carbon Isotope Stratigraphy of the Cambrian Sesong Formation in the Taebaeksan Basin, Korea (태백산 분지 캄브리아기 세송층의 암상과 안정 탄소 동위원소 층서)

  • Lim, Jong Nam;Chung, Gong Soo;Park, Tae-Yoon S.;Lee, Kwang Sik
    • Journal of the Korean earth science society
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    • v.36 no.7
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    • pp.617-631
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    • 2015
  • The Sesong Formation, mixed carbonate-siliciclastic deposits of late Middle Cambrian (Series 3) to Furongian in age, in the Taebaeksan Basin shows the Steptoean Positive Carbon Isotope Excursion (SPICE) with the ${\delta}^{13}C$ values ranging from 1.14 to 2.81‰ in the approximately 15-m-thick stratigraphic interval. The SPICE in the Sesong Formation occurs in the lower part of the Paibian Stage which contains trilobite biozones of the Fenghuangella laevis Zone, Prochuangia mansuyi Zone and the lower part of the Chuangia Zone. The Sesong Formation is composed of six lithofacies including laminated mudstone, nodular shale, laminated sandstone, massive sandstone, limestone conglomerate, and limestone-shale couplet facies. The Sesong Formation is known to have been deposited in the outer shelf below storm wave base. The SPICE occurs in the stratigraphic interval associated with highstand systems tract, correlative conformity and transgressive systems tract of the Sesong Formation. The peak carbon isotope value in the SPICE may coincide with the correlative conformity formed by relative sea-level fall. The occurrence of the SPICE in the Sesong Formation suggests that the SPICE can be used as a tool of global correlation for the successions of mixed carbonate-siliciclastics which lack fossils.