• Journal of Korea Water Resources Association
• /
• v.56 no.1
• /
• pp.11-21
• /
• 2023

This study suggests the drought resilience index as S-day as a means of preparing for the recent extreme drought, allowing for the actual operational identification of each drought countermeasure's priority as well as the vulnerability of water resource facilities to drought. Although each dam's drought measures are unique in this case, the representative examples include adjusting the water supply, linking the functioning of various facilities, and considering emergency capacity. Here, 15 multipurpose dams and water supply dams in Korea were inspected. Under the return period of 20-year drought, most of dams showed stable by adjusting the water supply overall. The measures, however, did not seem to be able to resist a multi-year drought lasting more than two years. Besides, Hoengseong and Anodong-Imha Dam only lasted a year under the 100-year drought return period with other measures. Without the deployment of drought mitigation strategies, it is expected that the Hoengseong Dam, Andong-Imha Dam, Gunwi Dam, Unmun Dam, Daecheong Dam, and Juam Dam would not be able to meet the all water demand for a year under the 20-year drought condition. The ideal capacity for each drought measure was then suggested. Additionally, by increasing or decreasing the current supply contract by 10% in order to account for demand changes resulting from socio-economic instability, the drought response capacity of all 15 dams was re-evaluated. By lowering the supply contract amount by 10%, it was possible to endure a severe drought.

• Korean Journal of Health Education and Promotion
• /
• v.4 no.2
• /
• pp.46-70
• /
• 1987

The survey with questionnaire were conducted to grasp the actual condition of four cautious drugs-antibiotics, sedative hypnctics, mincr tranquilizer, analeptics-self -medication behavior through drugstore use and to analyze the primary factors connected with it. The following six objectives were established. 1) To catch the reason why the man who medicate himself buy four cautious drugs at a drugstore, and to know the choice motive of each drug purchased. 2) To grasp the distribution of four cautious drug taken by the man who medicate himself and to analyse the reason of taking the drug. 3) To find out whether the buyer has taken the same drug past and to know the duration and the frequency. 4) To grasp the degree of recognition about four cautious drugs and the attitude toward continuous taking them. 5) To analyze the degree of recognition about the influence on human body and the attitude of medication behavior. 6) To know "the experience of side-effects" and to grasp the kind of the side-effects. The data were collected from 15 drugstores with 677 respondents in seoul from August 17 to september 21, 1987. The following results were obtained. 1) The reasons for drugstore use were first, "for easy access and convenience" (53.7%) second, "for the slightness of illness" (19.9%) third "for the cheap price" (13.2%). According to that result, the factor of "the easy access of drugstore" was most influential. In case of the poor, the factor "for the cheap price "was revealed second (37.3%). And "for the slightness of illness" was second reason in the medically insured (22. 9%), "for the cheap price" was second reason in the others (29%). 2) The kind of drugs purchased were antibiotics (62.8%), analeptics(17.2%), minor tranquilizer(13.3%) and sedative hypnotics (6.7%) on the whole. In teenagers, besides antibiotics the percentage of taking analepits came second (42.4%) and it was revealed that the percentage of sedative hypnotics, minor tranquilizer increase with age. But in proportion to the increase of age, the taking of analeptis decreased. 3) The choice motives of each drug purchased were all different. In case of antibiotics "recommendation of pharmacist" was 39.6%, sedative hypnotics "recommendation of pharmacist" and "my own judgement", 28.9%, respectively, minor tranquilizer "my own judgement", 35.2%. and in case of analeptics "my oun judgement" was most common with 53.5%. 4) The reasons for taking drugs were as follows. antibiotics was taken for the inflammation mitigation of a wound and a swelling (38.5%), sedative hypnotics for the removal of insomnia (97.5%), minor tranquilizer because of restlessness and qloominess(39.3%), and analeptics for the shortening of sleeping hours (35.1%). 5) Those experienced in taking four cautious drugs were 78.2% on the average. It was revealed that antibiotics use duration was "from one week to one month" (38.9%), the frequency was "rarely" (62.1%), sedative hypnotics and minor tranquilizer; "More than three years", (35.7%, 30.4%), respectively, "Somtimes", (43.8%, 35%), respectively. analeptics ; "from one year to three years", (27.6%), "Sometimes", (42.7%). 6) In regard to the source of information in taking drugs, 35.3 percent of male were relied on "recommendation of pharmacist", 32.6 percent of female "my own judgement", There was a difference between below the middle school graduates and over the high school graduates Thease were relied on "recommendation of pharmacist" first, those "my own judgement" first. And "my own judgement" was the first source of specialist(40%), labours(41.4%), salesman(43.5%), and jobless men(36.8%), "recommendation of ralatives on friends" was the first source of students (30.4%), "recommendation of pharmacist" was the first soure of teachers, administrative office workers (39%) and housewives (40.7%). 7) The degree of recognition about four cautious drugs was as follows. "know a little" was (43.0%), "don't know" (30.2%), "know" (26.8%), respectively. In regard to the attitude toward continuous taking them, it was revealed that "I will take it according to circumstamces" was first (56.2%), " I will not take it as possible" was first(56.2%), "I dont know well" (12.9%), "I will take it continuously" (8.3%). 8) About the influence on human body, "if proper, it is effect" was common attitude toward antibiotics (43.6%), "Probably bad influence on the health" was first toward the other drugs (46.2%), In terms of the degree of observance to taking-time and dose of drugs, "suitably" was first (37.3%), "relatively correctly" second (27%), "correctly" (17%). 9) The percentage of four cautious drugs side-effects was 27.5 on the average. The kind of side-effects were eruption and urticaria (28.5%), heart acceleration and so forth. (25.4%), headache and Giddiness, dyspepsia (23%), respectively.

• Korean Journal of Soil Science and Fertilizer
• /
• v.45 no.6
• /
• pp.1173-1178
• /
• 2012

Water competition among domestic, industrial and agricultural sectors has been gradually heightened recently in Korea as the lack of water supply is expected in the near future. About 46% of nation's water use is consumed in paddy farming to produce rice. And the conservation of water resource and quality in agricultural sector is a pending issue in the nation's long term water management plan. New paddy rice farming techniques that use significantly less irrigation water are urgently required. System of Rice Intensification (SRI) that is now well known to produce more rice with less water consumption has not been tried in Korea yet. And environmental effect of SRI on greenhouse gases (GHGs) has not been well investigated. The objective of this study was to measure the effect of SRI on GHGs as well as water use and rice yield in a Korean paddy condition. Three experimental runoff plots $5{\times}15m$ in size were prepared at an existing paddy field. Runoff, GHGs emission and water quality were measured during the 2011 growing seasons while a Japonica rice variety was cultivated. Rice plants grew better and healthier in SRI plots than in continuously flooded (CF) and intermittently drained (ID) plots. Rice yield from SRI plots increased 112.8 (ID)~116.1 (CF)% compared with CF and ID plots. Irrigation requirement of SRI plots compared to CF plot reduced by 52.6% and ID plot reduced by 62.0%, meaning that about 37.9~47.4% of irrigation water could be saved. GHGs emission from SRI plots reduced by 71.8% compared to that from CF plot and by 18.4% compared to that from ID plot, meaning that SRI could help contribute to ease the greenhouse gas accumulation in the atmosphere. It was believed that SRI is a promising paddy farming technique that could increase rice yield, and reduce irrigation water requirement and GHGs emission not just in Korea but also other rice farming countries all over the world. However, it was recommended that long term studies under different conditions including rice variety, soil texture, water source, climate need to be conducted for reliable data for the development of environmental policies related to GHGs emission control and management.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.65 no.2
• /
• pp.113-123
• /
• 2020

Global climatic change and increasing climatic instability threaten crop productivity. Due to climatic change, drought stress is occurring more frequently in crop fields. In this study, we investigated the effect of treatment with hydrogen peroxide (H₂O₂) before leaf development on the growth and yield of sorghum for minimizing the damage of crops to drought. To assess the effect of H₂O₂ on the growth of sorghum plant, 10 mM H₂O₂ was used to treat sorghum leaves at the 3-leaf stage during growth in field conditions. Plant height, stem diameter, leaf length, and leaf width were increased by 7.6%, 9.6%, 8.3% and 11.5%, respectively. SPAD value, chlorophyll fluorescence (Fv/Fm), photosynthetic rate, stomatal conductance, and transpiration rate were increased by 3.0%, 4.9%, 26.0%, 23.4% and 12.7%, respectively. The amount of H₂O₂ in the leaf tissue of sorghum plant treated with 10 mM H₂O₂ was 0.7% of the applied amount after 1 hour. The level increased to approximately 1.0% after 6 hours. The highest antioxidant activity measured by the Oxygen Radical Absorbance Capacity assay was 847.3 µmol·g^-1 at 6 hour after treatment. However, in the well-watered condition, the concentration of H₂O₂ in the plant treated by the foliar application of H₂O₂ was 227.8 µmol·g^-1 higher than that of the untreated control. H₂O₂ treatment improved all the yield components and yield-related factors. Panicle length, plant dry weight, panicle weight, seed weight per plant, seed weight per unit area, and thousand seed weight were increased by 8.8%, 18.0%, 24.4%, 24.7%, 29.9% and 7.1%, respectively. Proteomic analysis showed that H₂O₂ treatment in sorghum increased the tolerance to drought stress and maintained growth and yield by ameliorating oxidative stress.

• Korean Journal of Remote Sensing
• /
• v.33 no.5_3
• /
• pp.821-834
• /
• 2017

The increase in the rate of industrialization due to urbanization has caused the Urban Heat Island phenomenon where the temperature of the city is higher than the surrounding area, and its intensity is increasing with climate change. Among the cities where heat island phenomenon occurs, Seoul city has different degree of urbanization, green area ratio, energy consumption, and population density in each administrative district, and as a result, the strength of heat island is also different. So It is necessary to analyze the difference of Urban Heat Island Intensity by administrative district and the cause. In this study, the UHI intensity of the administrative gu and the administrative dong were extracted from the Seoul metropolitan area and the differences among the administrative districts were examined. and linear regression analysis were conducted with The variables included in the three categories(weather condition, anthropogenic heat generation, and land use characteristics) to investigate the cause of the difference in heat UHI intensity in each administrative district. As a result of analysis, UHI Intensity was found to be different according to the characteristics of administrative gu, administrative dong, and surrounding environment. The difference in administrative dong was larger than gu unit, and the UHI Intensity of gu and the UHI Intensity distribution of dongs belonging to the gu were also different. Linear regression analysis showed that there was a difference in heat island development intensity according to the average wind speed, development degree, Soil Adjusted Vegetation Index (SAVI), Normalized Difference Built-up Index (NDBI) value. Among them, the SAVI and NDBI showed a difference in value up to the dong unit and The creation of a wind route environment for the mitigation of the heat island phenomenon is necessary for the administrative dong unit level. Therefore, it is considered that projects for mitigating heat island phenomenon such as land cover improvement plan, wind route improvement plan, and green wall surface plan for development area need to consider administrative dongs belonging to the gu rather than just considering the difference of administrative gu units. The results of this study are expected to provide the directions for urban thermal environment design and policy development in the future by deriving the necessity of analysis unit and the factors to be considered for the administrative city unit to mitigate the urban heat island phenomenon.

• KEPCO Journal on Electric Power and Energy
• /
• v.1 no.1
• /
• pp.39-46
• /
• 2015

A outdoor termination installed at the outdoor substation is required to connect undergroud cables and overhead transmission lines. The joint box for AC transmission system is already developed and widely used to interconnect overhead and undergroud systems. But the development of the joint box for DC transmission system was only introduced from China and Japan, but theire developemnt staus and core technologies were not fully reported. In order to implement HVDC systems connecting ovehead transmission lines and undergroud cables, a outdoor termination should be developed, but the detailed specifications and information of this device were not reported. It is estimated that the development of the joint box for DC environment has some technical obstacles including insulating materials, electric field mitigation, thermal temperature rise, and space charge accumuations. Among this, the most important one is the DC elctrical insualtion design. Therefore, in order to investigate the DC elctrical insualton design of outdoor termination, the design of AC slip-on type outdoor termination is reffered, and DC electric field analysis performed to verify the possiblity of application of AC joint box into DC joint box. Especially for DC electric field analysis, temperature rise of insualting materials of a joint box was considered, because the conductivity of materials could be changed due to temperature rise. Furthermore, DC electric field analysis considering transinet state, and polarity reversal state were also investigated to verify which state is the most severe condition for the DC joint box. From the simualtion resulsts, it was shown that the value and the position of maximum electric field was obtained comparing AC state, DC state without temperaure rise, and DC state with temperaure rise. And it was confimred that severe DC electric field was observed considing temperaure rise. Finally, in order to reduce DC eletric field intensifation, different configuration of the joint box was applied and it was not possible to obtain satisfactory results. It means that the slight change of configuration of AC joint box was not the suitable soluton for DC joint box. It is essential to establish novel DC insulaton design skills and method for DC joint box to commercialze this product in the near future.

• Economic and Environmental Geology
• /
• v.54 no.2
• /
• pp.177-186
• /
• 2021

For disaster management and mitigation of earthquakes in Korea Peninsula, active fault investigation has been conducted for the past 5 years. In particular, investigation of sediment-covered active faults integrates geomorphological analysis on airborne LiDAR data, surface geological survey, and geophysical exploration, and unearths subsurface active faults by trench survey. However, the fault traces revealed by trench surveys are only available for investigation during a limited time and restored to the previous condition. Thus, the geological data describing the fault trench sites remain as the qualitative data in terms of research articles and reports. To extend the limitations due to temporal nature of geological studies, we utilized a terrestrial LiDAR to produce 3D point clouds for the fault trench sites and restored them in a digital space. The terrestrial LiDAR scanning was conducted at two trench sites located near the Yangsan Fault and acquired amplitude and reflectance from the surveyed area as well as color information by combining photogrammetry with the LiDAR system. The scanned data were merged to form the 3D point clouds having the average geometric error of 0.003 m, which exhibited the sufficient accuracy to restore the details of the surveyed trench sites. However, we found more post-processing on the scanned data would be necessary because the amplitudes and reflectances of the point clouds varied depending on the scan positions and the colors of the trench surfaces were captured differently depending on the light exposures available at the time. Such point clouds are pretty large in size and visualized through a limited set of softwares, which limits data sharing among researchers. As an alternative, we suggested Potree, an open-source web-based platform, to visualize the point clouds of the trench sites. In this study, as a result, we identified that terrestrial LiDAR data can be practical to increase reproducibility of geological field studies and easily accessible by researchers and students in Earth Sciences.

• Journal of the Korea Organic Resources Recycling Association
• /
• v.30 no.4
• /
• pp.67-83
• /
• 2022

Biochar is a carbon material produced through the pyrolysis of agricultural biomass with limited oxygen condition. It has been suggested to enhance the carbon sequestration and mineralization of soil carbon. Objective of this study was to investigate soil potential carbon mineralization and carbon dioxide(CO₂) emissions in different soils cooperated with barely straw and livestock manure biochars in the closed chamber. The incubation was conducted during 49 days using a closed chamber. The treatments consisted of 2 different biochars that were originated from barley straw and livestock manure, and application amounts were 0, 5, 10 and 20 ton ha^-1 with different soils as upland, protected cultivation, converted and reclaimed. The results indicated that the TC increased significantly in all soils after biochar application. Mineralization of soil carbon was well fitted for Kinetic first-order exponential rate model equation (P<0.001). Potential mineralization rate ranged from 8.7 to 15.5% and 8.2 to 16.5% in the barely straw biochar and livestock manure biochar treatments, respectively. The highest CO₂ emission was 81.94 mg kg^-1 in the upland soil, and it was more emitted CO₂ for barely straw biochar application than its livestock biochar regardless of their application rates. Soil amendment of biochar is suitable for barely straw biochar regardless of application rates for mitigation of CO₂ emission in the cropland.

• Journal of Korea Water Resources Association
• /
• v.54 no.8
• /
• pp.577-587
• /
• 2021

Drought is generally considered to be a natural disaster caused by accumulated water shortages over a long period of time, taking months or years and slowly occurring. However, climate change has led to rapid changes in weather and environmental factors that directly affect agriculture, and extreme weather conditions have led to an increase in the frequency of rapidly developing droughts within weeks to months. This phenomenon is defined as 'Flash Drought', which is caused by an increase in surface temperature over a relatively short period of time and abnormally low and rapidly decreasing soil moisture. The detection and analysis of flash drought is essential because it has a significant impact on agriculture and natural ecosystems, and its impacts are associated with agricultural drought impacts. In South Korea, there is no clear definition of flash drought, so the purpose of this study is to identify and analyze its characteristics. In this study, flash drought detection condition was presented based on the satellite-derived drought index Evaporative Stress Index (ESI) from 2014 to 2018. ESI is used as an early warning indicator for rapidly-occurring flash drought a short period of time due to its similar relationship with reduced soil moisture content, lack of precipitation, increased evaporative demand due to low humidity, high temperature, and strong winds. The flash droughts were analyzed using hydrometeorological characteristics by comparing Standardized Precipitation Index (SPI), soil moisture, maximum temperature, relative humidity, wind speed, and precipitation. The correlation was analyzed based on the 8 weeks prior to the occurrence of the flash drought, and in most cases, a high correlation of 0.8(-0.8) or higher(lower) was expressed for ESI and SPI, soil moisture, and maximum temperature.