• Journal of Korea Water Resources Association
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• v.55 no.12
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• pp.1021-1030
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• 2022

Currently, South Korea implements water resources management policies focusing on integrated water quantity, quality and hydro-ecology management. In particular, rehabilitation of natural rivers has become a major issue. As for reservoir operation during non-flood season, efforts have been made continuously to apply the Deficit Supply Method that can maximize water supply to address droughts and increase in water demand. When Deficit Supply Method is applied, the water supply capacity of reservoir can be maximized. However, downstream water flow would remain constant. In consideration that a natural stream, a long-time-created hydro-ecology, can be significantly influenced by flow variability, the Deficit Supply Method-based reservoir operation can generate effective water supply. Still, it may trigger adverse effects from the aspects of natural rehabilitation and hydro-ecology recovery. The main objective of this study is to analyze impacts on downstream flow duration through reservoir simulation by comparing the Firm Supply Method, the Deficit Supply Method and the Selective Deficit Supply Method, and examining each method's effects on reservoir operation. This study found that the Firm Supply Method could maintain water flow variability, but could not maximize water supply capacity. When the Deficit Supply Method was applied, water supply capacity could be increased while remaining vulnerable regarding water flow variability, as a difference between average flow and low flow was negligible at downstream. In comparison, the Selective Deficit Supply Method was found to sustain time-based reliability at 95% or higher, whereas downstream flow duration could be maintained at a level similar to the level generated by the Firm Supply Method.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.2
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• pp.56-63
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• 2018

The management of Combined Sewer Overflows(CSOs) and Separated Sewer Overflows(SSOs) discharge directly to the effluent system in an untreated state, which occurs when the facility capacity is exceeded due to heavy rain, has become an important issue in recent years as the heavy rain becomes a regular phenomenon. Despite the continuous development of filtration technology, targeting densely populated urban areas, CSOs are rarely applied. Therefore, this study was carried out to optimize the process to apply CSOs in a pilot-scale horizontal flow filtration system with a rope-type synthetic fiber. The research was carried out in two steps: a preliminary study using artificial samples and a field study using sewage. In the preliminary study using an artificial sample, head loss of the filter media itself was analyzed to be approximately 1.1cm, and the head loss was increased by approximately 0.1cm as the linear velocity was increased by 10m/hr. In addition, the SS removal efficiency was stable at 81.4%, the filtration duration was maintained for more than 6 hours, and the average recovery rate of 98% was obtained by air backwashing only. In the on-site evaluation using sewage, the filtration duration was approximately 2 hours and the average removal efficiency of 83.9% was obtained when belt screen (over 450 mesh) was applied as a pre-treatment process to prevent the premature clogging of filter media. To apply the filtration process to CSOs and SSOs, it was concluded that the combination with the pre-treatment process was important to reinforce the hydraulic dimension for the stable maintain of operation period, rather than efficiency. Compared to the dry season, the quality of incoming sewage was lower in the rainy season, which was attributed to the characteristics of the drainage area with higher sanitary sewerage. In addition, the difference in removal efficiency according to the influent quality of the wet season and dry season was small.

• Journal of Korean Society on Water Environment
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• v.37 no.4
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• pp.249-262
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• 2021

This study investigated the pollution characteristics of the main pollution zone in the Hwangguji watershed and the influence of the tributary on the main stream. The characteristics of the main pollution zone, including, the water quality index (WQI), stream rating, load duration curve (LDC), delivery load density (DLD), and contribution of the tributary to the mainstream, were evaluated by time-series visual heatmap. The WQI of the mainstream of Hwangguji was lowered to the poor (IV) level from the inflow point of Suwon stream (SW) and the LDC excess rate in the T-P was higher than that of BOD₅, especially for the wet season, suggesting that management of non-point source with T-P is preferred. The contribution (%) of the tributaries in the upstream section of Hwangguji watershed were BOD₅ 14.54%, TOC 15.67%, T-N 5.43%, and T-P 6.97%. In particular, the Suwon sewage treatment plant located in the mainstream showed a high contribution of BOD₅ (64.40%) and T-P (53.54%), respectively, due to the high discharge rate (6.019 m³/sec). Meanwhile, Sammi and Gal stream have a large impact on the mainstream with high DLD and poor WQI. Thus, both streams were considered as pollution hot spots. These results provide useful basic data for preparing more effective water quality improvement and management plans in the watershed.

• Journal of Environmental Science International
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• v.27 no.10
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• pp.845-851
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• 2018

In this study, the runoff characteristics of the non-rainfall period were examined using daily rainfall data from 1977 to 2017 and the data of runoff into the dam. Results showed that, the mean runoff decreases with longer non-rainfall periods in the Andong dam basin. The correlation coefficient between non-rainfall days and average runoff reaches 0.85. The results of the analysis of the runoff characteristics during the non-rainfall period, based on the preceding rainfall of Andong dam are as follows. The runoff characteristics of the entire non-rainfall period, shows that, for a rainfall of 1.0 mm or less, the runoff height was larger than the rainfall size and the base runoff larger. The correlation between the antecedent rainfall and runoff height was reached as high as 0.9864 in the 30 ~ 50 mm interval of the antecedent rainfall period, and this is the interval where the linearity of rainfall and runoff was at its maximum in the Andong dam basin. The correlation between the antecedent rainfall and the runoff height reached 0.92 for rainfalls of 100.0 mm. However, for rainfalls of 100.0 mm greater, the correlation between the antecedent rainfall and runoff height during the rainfall period was 0.64, which is relatively small. In this study, we investigated the runoff characteristics of the rainfall period in the Andong dam watershed. As a result, it was confirmed that the mean runoff decreased with rainfall duration. The linearity was found to be weak for rainfall events greater than 100.0 mm. The results of this study can be used as data for water balance analysis and for formulating a water supply plan to establish water resource management of Andong dam.

• Journal of Ecology and Environment
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• v.37 no.4
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• pp.165-175
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• 2014

A natural population of Adonis multiflora, a spring ephemeral herb growing in temperate deciduous forests, was studied to determine the seed production characteristics. Plant size, flowering time, and seed number were monitored from February 2009 to May 2011 in main growing season (i.e., from March through May). The biomass rates of the shoot and the root in the A. multiflora population were 22-24% and 76-78%, respectively, and the biomass of the root was proportional to that of the shoot. The flowering rate was 60% in the plants with 1 to 2 g of shoot biomass, and 100% in the plants with >2 g of shoot biomass. In the plants with root biomass between 4 and 6 g, the flowering rate was 43% and, in the plants with the root biomass over 8 g, it was 100%. The shoot biomass was a better predictor of the flower production probability than the root biomass. The number of flowers and seeds was closely correlated to shoot biomass at 1% significance level. The size of the plant that produced seed excessively instead of the shoot biomass in one year typically decreased in the next year and vice versa. The flowering time and its duration were closely related to the number of faithful seeds but not to that of total seeds. The number of faithful seeds was proportionate to flowering duration and inversely proportionate to flowering time (year day, YD). In a plant, the number of faithful seeds noticeably decreased with the inflorescence (i.e., order of flower in a plant), and this difference between the two successive flowers was significant at the 1% level between the first and the third flower in 2009 and 2011 but not between the third and the fourth. However, the number of total seeds was mostly similar in the first through the fourth flower for all three years.

• Korean Journal of Agricultural and Forest Meteorology
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• v.7 no.4
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• pp.250-257
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• 2005

This study was conducted to investigate the effect of meteorological elements on the changes of inorganic nutrient contents in leaves of 'ruyu' and 'Nishimurawase' sweet persimmon during the growing season. The contents of N, P, K and Cu decreased in leaves of 'Fuyu' and 'Nishimurawase' sweet persimmon during vegetative growth, while Ca, Mg and Mn increased. The K content was higher in leaves of 'Fuyu' than in 'Nishimurawase' sweet persimmon. The P and Ca content was higher in 'Nishimurawase' leaves than in 'Fuyu' sweet persimmon. Mean temperature was positively correlated with content of P in leaves. Rainfall was positively correlated with the content of Ca in leaves, whereas it was negatively correlated with content of N and Cu in leaves. The duration of sunshine was positively correlated with N and Cu in leaves but negatively correlated with that of Ca, Mg, and Mn content.

• Journal of the Korean Burn Society
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• v.24 no.1
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• pp.7-13
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• 2021

Purpose: Currently, the most recommended method for burn first aid is the cool running water for 20 minutes (CRW20). If CRW20 is not practicable, cooling dressing products with tea tree oil are used as substitutes. In this study, we analyze the effect of various burn first aids, including CRW20, cooling products, on the treatment period. Methods: This study was conducted on patients who suffered burns and visited Hangangsoo Hospital from March 2019 to March 2020. The study conducted in a retrospective method. The duration of treatment was analyzed by dividing the experimental group. Results: The treatment period was shortened when first aid was given (P<0.001). Cold water, ice, and ice packs resulted in reduced treatment periods (P<0.001, P=0.004). The treatment period was reduced when cooling dressing products were used in all groups (P=0.041). The implementation of first aid has reduced the duration of burn treatment. This means that cooling helps burn treatment. CRW20 did not show statistically meaningful results. This is the result of a failure to fully control the temperature and time of tap water. In addition, the change in temperature of tap water according to season, the use of water is higher than that of animal testing, and the general lack of information on proper burn first aid may have affected. Conclusion: The treatment period was statistically significantly reduced in the group that performed first aid. Among the various first aid methods, cold water and ice reduced the treatment period.

• Korean Journal of Agricultural Science
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• v.29 no.1
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• pp.15-23
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• 2002

The percentage of watercore occurrence harvested on Nov. 6 (commercial harvest season) was over 80% but fruits seemed not to reach climacteric stage on the basis of ethylene evolution. The occurrence ratio and severity of watercore gradually decreased with the increase of preshipment storage for 2 months. The level of soluble solids did not show a clear tendency during preshipment storage but flesh firmness, fresh weight, and acidity gradually decreased. Although the overall quality of fruit reduced along with the increase of preshipment storage duration after exposure to retail condition at ambient temperature for 1 week, plastic film wrapping (PE 30 um) as well as plastic film wrapping plus ethylene scrubbing had a benefit on keeping freshness of fruit even after retail condition. Waxed fruit showed excellent appearance but browning disorder was developed. Results indicated that moisture barrier such as plastic film wrapping and ethylene removal have a great potential on keeping freshness of fruit during export which required long-term transport under low humidity environment.

• Clinical and Experimental Pediatrics
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• v.59 no.9
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• pp.368-373
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• 2016

Purpose: This study examined the risk factors of a delayed diagnosis of acute appendicitis in children undergoing an appendectomy. Methods: This retrospective study involved children aged below 18 years, who underwent an appendectomy. After dividing them into a delayed diagnosis group and nondelayed diagnosis group according to the time interval between the initial hospital visit and final diagnosis, the risk factors of delayed diagnosis were identified using logistic regression analysis. Results: Among 712 patients, 105 patients (14.7%) were classified in the delayed diagnosis group; 92 patients (12.9%) were diagnosed using ultrasonography (US), and both US and computed tomography were performed in 38 patients (5.3%). More patients in the delayed diagnosis group underwent US (P=0.03). Spring season and prior local clinic visit were significantly associated with a delayed diagnosis. Fever and diarrhea were more common in the delayed diagnosis group (fever: odds ratio [OR], 1.37; 95% confidence interval [CI], 1.05-1.81; diarrhea: OR, 1.94; 95% CI, 1.08-3.46; P<0.05). These patients showed symptoms for a longer duration (OR, 2.59; 95% CI, 1.78-3.78; P<0.05), and the admission course (OR, 1.26; 95% CI, 1.11-1.44; P<0.05) and C-reactive protein (CRP) levels (OR, 1.47; 95% CI, 1.19-1.82; P<0.05) were associated with the delayed diagnosis. Conclusion: To decrease the rate of delayed diagnoses of acute appendicitis, symptoms such as fever and diarrhea, seasonal variations, admission course, and CRP levels should be considered and children with a longer duration of symptoms should be closely monitored.

• The Journal of Internal Korean Medicine
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• v.14 no.1
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• pp.71-81
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• 1993

Clinical observation was done on 372 Cheon-Jeung patients more than 65 years of age in Department of Internal Medicine, Oriental Medical Hospital in Dong Guk Univ. from December 1990 to November 1991. The results were as follows; 1. The ratio of male to female was 1.2:1. The age distribution showed the large number in the 65-69 year group, the female more than the male in 8th decade. 2. The peak age in the on set was 7th decade(44.4%). 3. The ratio of the season distribution was as follows, everytime 62.6%, fall and winter 25.5%. 4. Duration from on set, the most frequence was $5{\sim}10$ years(29.6%). 5. Chief complaints were represented cough, laryngeal stridorand, dyspnea. 6. In past illness, Pulmonary. The was most predominent(29.7%) followed by allergic disease(8.1%), bronchitis(7.2%) in turn. 7. In complication, Pul. Tbc was most predominent(21.1%) followed by ronchiectasis (12.7), cardiac disease(11.3%). 8. Predisposing factors in the Geriatric athma were represented chiefly exercising(41.8%), the others is Pung-Han-Neng(27.6%), respiratory infection(12.7%) etc. 9. The recipe which used in treatment were Gamigeumsuyukgun-jeon, Gamimahwangyunpai-tang, Gamiyunpai-tang, Sojaganggi-tang, Cheongsangboha-tang etc. 10. Duration of treatment was noted within 10 days was 39.2%, $11{\sim}30$ days was 40.6%, over 60 days was 7.3%. 11. About 77.3% patients were improved.