• Journal of Korean Society on Water Environment
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• v.25 no.5
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• pp.792-802
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• 2009

The objective of this study is to construct the watershed management system with link of the non-point sources model and to estimate delivery ratio duration curves for various pollutants. For the total water pollution load management system, non-point source model should be performed with the study of the characteristic about non-point sources and loadings of non-point source and the allotment of pollutant in each area. In this study, daily flow rates and delivered pollutant loads of Nakdong river basin are simulated with modified TANK model and minimum variance unbiased estimator and SWAT model. Based on the simulation results, flow duration curves, load duration curves, and delivery ratio duration curves have been established. Then GIS analysis is performed to obtain several hydrological geomorphic characteristics such as watershed area, stream length, watershed slope and runoff curve number. As a result, the SWAT simulation results show good agreements in terms of discharge, BOD, TN, TP but for more exact simulation should be kept studying about variables and parameters which are needed for simulation. And as a result of the characteristic discharges, pollutants loading with the runoff and delivery ratios, non-point sources effects were higher than point sources effects in the small-scale test bed of Nakdong river basin.

• Journal of Korean Society on Water Environment
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• v.25 no.4
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• pp.580-588
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• 2009

In this study daily flow rates and delivered pollutant loads of Nakdong river basin are simulated with modified TANK model and minimum variance unbiased estimator. Based on the simulation results, flow duration curves, load duration curves, and delivery ratio duration curves have been established. Then GIS analysis is performed to obtain several hydrological geomorphic characteristics such as watershed area, stream length, watershed slope and runoff curve number. Finally, multiple regression analysis is carried out to estimate empirical equations for pollutants delivery ratio. The results show that there is positive relation between the flow rates and delivery ratios, and the proposed empirical formulas for delivery ratio can predict well river pollutant loads.

• Journal of Korean Society of Water and Wastewater
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• v.18 no.6
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• pp.748-757
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• 2004

In this study, we analyzed the sensitivity of parameters which affect the result of ILLUDAS model, in the various rainfall conditions. The three basins including Namgaja, Kings creek, Gray haven were selected for this research. The rainfall conditions are considered in terms of the rainfall frequency, the duration and the distribution. In most cases, the impermeability area ratio, the sewer slope, and the sewer roughness coefficient give more significant effects on the results than others. The results show that as increasing the rainfall frequency, the sensitivity of the parameters, sewer slope and roughness coefficient are rised, while the impermeability area ratio is decreasing. And also, for the duration of rainfall, the impermeability area ratio's sensitivity shows similar tendency. In case of the rainfall distribution, the parameters of the sewer roughness and the impermeability area ratio show more sensitive in Huff distribution. Especially, The impermeability area ratio is the most sensitive parameter in Central blocking and Yen & Chow distributions respectively.

• Speech Sciences
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• v.9 no.1
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• pp.193-206
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• 2002

The aim of this study is to find out how the labiovelar onglide /w/ in English kwV sequences that have minimal pairs with kV sequences is pronounced differently among Korean EFL learners based on acoustic evidence. This study tries to identify /w/ sound in English kwV sequences through spectrograms and to examine the duration ratios of each segment in kwV words to compare the patterns of an English native speaker with those of Korean speakers of English. In spectrographic analyses, the complete deletion of /w/ and partial pronunciation of /w/ dubbed [$k^{w}$] were identified as well as the targetappropriate production of /w/. The general production patterns with respect to the duration ratios in English [kw] sequence words showed that the subjects who produced /w/ had similar ratio patterns that the native speaker had in that the vowel duration ratio in kwV sequences was shorter than that in kV sequences. By contrast, the subjects who deleted [w] had a long ratio of the onset [$k^{h}$] while the speaker with a partial pronunciation of /w/ had a long ratio of the following vowel.

• Atmosphere
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• v.16 no.2
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• pp.55-65
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• 2006

The characteristics of Depth-Area-Duration (DAD) for 50 storms over the Geumgang river basin have been analysed in terms of various storm causes using the precipitation data during the period from 1984 to 2003. Results show that the ratio of the precipitation depth to duration, and the ratio of decrease in the precipitation depth to area are the largest in the case of the tropical cyclone. Storm maximization ratios are in the range 1.03 to 2.66 for the 50 selected heavy precipitation cases over Geumgang river basin, with the largest value for the tropical cyclone case, suggesting that the tropical cyclone could cause heavier precipitation than the other storms. In addition, the 24-hour probable maximum precipitation for the Geumgang river basin is estimated to be about 745 mm in the maximum precipitation area.

• Journal of Korean Society of Water and Wastewater
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• v.19 no.5
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• pp.619-624
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• 2005

This work is for examining a simplified equation based on the rational formula, which can easily decide storm-water detention volume in small urban catchments. The storm-water detention volume is determined by the inflow hydrograph flowing to detention basin and the outflow hydrograph discharged from the detention basin. The ratio of average outflow over the period of rainfall duration against allowable discharge was 0.5 in former simplified equation. But this research has found that the average outflow ratio depends on the storage methodology. In the case of the on-line storage method, the average outflow ratio is a function of the time of concentration of the catchments and rainfall duration, which ranged from 0.5~1.0. In the case of the off-line storage method, the average ratio is a function of peak discharge and allowable discharge except above time of concentration and rainfall duration, where its function value ranged from 1.0~2.0. When applying this equation to small catchment in Mokpo city, South Korea, we could easily calculate the relation curve between the storm-water detention volume and allowable discharge.

• Journal of the Korean Dietetic Association
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• v.29 no.1
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• pp.31-48
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• 2023

This study evaluated the nutrient adequacy ratio (NAR) and depression based on the sleep duration of adult women using data from the Korea National Health and Nutrition Examination Survey (KNHANES) 2016 and 2018. A total of 4,507 subjects were divided into two groups: sleep hours<7 (lack of sleep, LS) and 7≤sleep hours (normal sleep, NS). For a more detailed analysis, the subjects were further divided into normal sleep with no depression (NSND) and lack of sleep with depression (LSWD) groups. When compared with NS group, the nutrient intake of the LS group was observed to be higher in carbohydrates (P<0.05) and thiamine (P<0.01), but had a significantly lower mean nutrient adequacy ratio (P<0.05). Also, the LS group showed a higher frequency of early menopause (P<0.001) and depression (P<0.05) than the NS group. In the analysis of anthropometry and blood parameters of the subjects based on their sleep duration, the LS group showed a lower body mass index (BMI, P<0.05), lower blood creatinine (P<0.01), glycated hemoglobin (P<0.05), and high-density lipoprotein (HDL) cholesterol (P<0.01) levels adjusted by age and menopause than the NS group. When compared to the NSND group, the LSWD group had a lower intake of cholesterol (P<0.05), vitamin A (P<0.05), vitamin C (P<0.05), and folic acid (P<0.05). There was no variation in the menopausal status, NAR, and mean nutrient adequacy ratio between the NSND and LSWD groups. However, there were differences in total blood cholesterol (P<0.05) and depression based on sleep duration. Apart from nutritional status, differences in BMI and blood parameters were observed based on sleep duration.

• Phonetics and Speech Sciences
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• v.4 no.4
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• pp.117-127
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• 2012

This research reports the prosodic characteristics (including articulation speech rate, pause characteristics, duration) of children with cochlear implants with reference to those of children with normal hearing. Subjects are 8-to 10-year-old children, balancing each number of gender as 24. Dialogue speech data are comprised of four types of sentence patterns. Results show that 1) there's a statistically meaningful difference on articulation speech rate between the two groups. 2) On pauses, they are not observed in exclamatory and declarative sentences in normal children. While imperative sentences show no statistical difference on the number of pauses between the two groups, interrogative sentences do. 3) Declarative, exclamatory, and interrogative sentences reveal statistical difference between the two groups in terms of the sentence's final two-syllable word duration, showing no difference on imperative sentences. 4) When it comes to the RFP (duration ratio of sentence final syllable to penultimate syllable), we no statistically meaningful difference between the two groups in all types of sentences exists. 5) Lastly, RWS (the ratio of sentence final two syllable word duration to that of whole sentence duration) shows statistical difference between two groups in imperative sentences, but not in all the rest types.

• Clinical and Experimental Pediatrics
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• v.53 no.4
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• pp.579-584
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• 2010

Purpose : The number of the repatriated Korean students who had overseas study at early ages is increasing. They received foreign education, they can speak international languages, but they have many difficulties in articulation and intonation of the Korean language. This study aims to measure closure and aspiration duration, length of consonants, length of subsequent vowels, and ratio of consonants against subsequent vowels in vowel-consonant-vowel (VCV) syllables. Methods : This study compares the acoustic and phonetic characteristics of repatriated and native students, the ratio of articulation error of Korean plosives, the closure and aspiration duration, and the ratio of the aspiration duration against the closure duration. Results : The ratio of articulation error of Korean plosives between repatriated and native students is 19% and 2%, respectively. The closure duration was significantly longer in repatriated students than in native students. The aspiration duration was significantly longer in repatriated students than in native students. No difference was found in the ratio of aspiration duration against closure duration between the native and repatriated students. Conclusion : This study can be a good reference for estimating the phonetic difficulties of Korean elementary students who had overseas study at early ages.

• Nutrition Research and Practice
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• v.5 no.2
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• pp.157-162
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• 2011

The importance of dietary intake in the treatment of type 2 diabetes was emphasized. This study was performed to investigate the dietary intakes of Korean type 2 diabetes patients according to the treatment and duration of diabetes and to examine the relationships between their diet and serum lipid profiles. The subjects were 111 type 2 diabetic patients who were treated by medical nutrition therapy only, oral hypoglycemic agents (OHA), or insulin with medical nutrition therapy. Dietary intake was assessed by a registered dietitian using semi-quantitative food frequency questionnaires Comparisons according to treatment type were made using covariance analyses. General linear models identified the independent effects of the different treatments after covarying for age, duration of diabetes, and 2-way interactions. There were no significant differences in age and BMI but was in duration of diabetes according to treatment type in these subjects. Carbohydrate to energy ratio was higher in the OHA group (P < 0.05), whereas the fat to energy ratio was higher in the insulin group for males (P < 0.05). Carbohydrate ($R^2$ = 0.24, P = 0.005) and fat ($R^2$ = 0.26, P = 0.02) to energy ratios were independently associated with the duration of diabetes after covarying for age, sex, treatment, and 2-way interactions. The levels of triglyceride (TG; $R^2$ = 0.32, P = 0.02) and total cholesterol (TC) were associated independently with energy intake and the carbohydrate ($R^2$ = 0.15, P = 0.02) and fat ($R^2$ = 0.15, P = 0.01) to energy ratios, respectively. The concern that the independent association of dietary intake with either duration of diabetes or dietary factors affects blood lipid levels could suggest that specific dietary recommendations may work better for identifiable groups of diabetes patients.