• 한국농공학회논문집
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• 제53권3호
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• pp.53-58
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• 2011

This study is analyzed the characteristics of the soil erosion with the geotechnical conditions and rainfall conditions, such as the ground slope, the compaction ratio, rainfall intensity and duration of rainfall etc. To this ends, a series of model test are conducted on clayey sands. From the results, the variation of soil loss is analyzed with the geotechnical and the rainfall conditions. The amount of soil loss is decreased as the increase of compaction ratio and is increased as the ground slope, rainfall intensity and the duration of rainfall.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제50권7호
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• pp.329-333
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• 2001

The pulsed poser system has been widely used to many applications, such as E/P(Electrostatic Precipitator), DeNox/DeSOx power system, ozon generator, etc. A pulse energy efficiency for load depends on the rising time, peak value, pulse duration and impedance matching, etc. The pulse generator generally required for short pusle duration and high peak value was forced to consider its volume and economy. In this study, developing a compact pulse generator that applied for cascading method to be made of two pulse transformers, we compared cascading voltage with non cascading one by applying the pulse energy to load. Adopting cascading technique to pulse transformer, we found that average cascading voltage was about 60[%] of theoretical value. Maximum cascading ratio was calculated at 60 times compared with non cascading voltage.

• 한국자동차공학회논문집
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• 제13권1호
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• pp.28-35
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• 2005

Fuel injection rate of an injector is affected by various injection conditions such as injection duration, fuel temperature, injection pressure, and voltage in LPG liquid injection systems for either a port-fuel-injection(PFI) or a direct injection(DI) in a cylinder. Even fuel injection conditions are changed, the air-fuel ratio should be accurately controlled to educe exhaust emissions. In this study, correction factor for the fuel injection rate of an injector is derived from the density ratio and the pressure difference ratio. A voltage correction factor is researched from injection test results on an LPG liquid injection engine. A compensation method of the fuel injection rate is proposed for a fuel injection control system. The experimental results for the LPG liquid injection system in a SI-engine show that this system works well on experimental range of engine speed and load conditions. And the fuel injection rate is accurately controlled by the proposed compensation method.

• 한국수자원학회논문집
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• 제36권3호
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• pp.385-398
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• 2003

내배수시설계획시 최대저류비에 의한 유수지 규모의 결정 방법은 이전 연구자에 의하여 제시된 바 있다. 본 연구에서는 동두천시 11개 소규모 내배수시설을 선정하여 분석한 결과, 배수면적이 작고 펌프기능이 강화된 내배수 시설에서는 강우지속기간별 우수지의 저류비의 차이는 미미하므로 최대저류비에 의한 조정지 규모의 결정은 무리가 있음을 알 수 있었다. 또한 최대저류비에 의하여 결정된 조정지 용량을 펌프에 의하여 배제되는 시간은 펌프의 허용시동간격보다 짧은 경우도 있어 펌프의 빈번한 작동을 초래한다. 그러므로 조정지는 펌프의 빈번한 작동에 의한 펌프 고장의 가능성을 피할 수 있는 규모로 결정되어야 한다. 다양한 펌프용량을 적용하여 분석한 결과, 소유역에서도 조정지의 기능이 강화된 내수배제시설에서는 최대저류비를 기준으로 한 조정지 용량의 결정은 펌프운영 측면에서 타당함을 알 수 있었다. 따라서 본 연구에서는 소규모 배수구역에서 조정지용량의 결정시 펌프의 계획배수량과 유수지의 용량에 따른 펌프의 시동빈도를 반영하여 기존의 최대저류비에 의한 방법을 개선한 방안을 제시하였다. 또한 유수지 규모와 펌프용량의 관계를 간단한 선형계획모형으로 분석한 결과, 종래의 유수지 홍수추적에 의한 유수지 용량 결정은 도시지역의 내배수시설 계획에만 타당함을 알 수 있었다.

• 물과 미래
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• 제26권1호
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• pp.115-124
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• 1993

본 연구는 유수지.배수펌프장설계를 위한 계획강우의 임계지속기간의 결정 및 이에 근거한 계획 유수지.배수펌프장의 적정규모 추정에 관한 것이다. 계획강우의 지속기간과 시간적 분포형의 변화에 따른 영향을 파악하기 위하여 20~240분 범위의 9가지 경우의 지속기간들과 Huff의 4분위법에 의한 4종류의 강우분포들을 검토대상 강우로 선택하였으며, 유출해석모형으로는 ILLUDAS를 사용하였다. 임계지속기간 결정기준으로서 저류비(총유출량에 대한 최대저류량의 비)의 개념을 도입하였으며, 이 값을 최대로 하는 지속기간을 계획강우의 임계지속기간으로 하였다. 본 연구를 위하여 배수구역면적이 $0.24~12.7\textrm{km}^2인$ 서울시의 18개 유수지.배수펌프장을 선정하였으며, 분석 결과 전반적으로 30분과 60분이 임계지속기간으로 나타났다. 도한 Huff의 제 2, 3분위형의 경우가 제 1, 4분위형 보다 큰 저류비를 보여주었다. 또한 임계지속기간을 갖는 강우조건에서의 최대저류비와 첨두입출비간의 회귀식을 제시하였다. 이 관계식은 유수지 배수펌프장 계획수립에 활용될 수 있을 것으로 기대된다.

• 원예과학기술지
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• 제19권3호
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• pp.362-366
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• 2001

1998년 8월 중순 경북 북부지역에 있었던 집중호우에 의한 하천 범람으로 침수된 과수원을 군위, 의성, 안동에서 지역별 6개 과수원씩, 총 18개 과수원을 대상으로 '후지' 사과나무의 생육 상황과 주요 병해 이병률을 조사하였다. 조사 과수원의 침수 깊이는 70cm-350cm였고, 침수 기간은 6시간-72시간이었다. 침수 피해 사과원의 낙엽률, 발아율 및 이상개화 현상은 침수 깊이가 깊을수록, 침수 기간이 길어질수록 증가하였다. 새 뿌리 발생은 침수 기간이 길어질수록 급격히 감소하였고, 침수로 인한 뿌리 고사율은 16.2%로 나타났다. 잎의 갈색무늬병, 과실의 부패병, 역병 발생이 무침수 과원에 비해 크게 증가하였고, 조사 항목 간 상관분석 결과, 침수에 의한 이상 생육과 발병 증가가 침수 깊이보다는 침수 기간에 더 큰 영향을 받는 것으로 조사되었다.

• 음성과학
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• 제7권2호
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• pp.51-70
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• 2000

Twenty normal and 20 severe-to-profound hearing-impaired subjects participated in the present study. The two groups are matched by their chronological age. Each subject made a recording of three vowels of /i/, /a/, and /u/, and nine $VC_{plosive}V$ (hereafter, VCV) disyllables of /epe/, /ep'e/, /$ep^{h}e$/, /ete/, /et'e/, /$et^{h}e$/, /eke/, /ek'e/, and /$ek^{h}e$/, each five times. Formant frequencies of $F_1,\;F_2,\;and\;F_3$ were measured for the three vowels and six measures were made for the nine disyllables. The six measures were (1) the total duration of the disyllable, (2) the duration of the first vowel, (3) the duration of the closed period, (4) the ratio of the first vowel over the first vowel plus the closure period of the consonant, (5) the duration of the aspiration, and (6) the duration of the second vowel. Results shows that the three formants and each of the measures were significantly different between the two groups of subjects.

• 성인간호학회지
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• 제26권3호
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• pp.372-381
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• 2014

Purpose: This study investigated the prevalence of hypertension, explored sleep duration, and examined the related factors to hypertension in Korean middle-aged adults. Methods: Using raw data from the Korean National Health and Nutritional Examination Survey (KNHANES) conducted from 2008 to 2010, a secondary analysis was performed with data from 13,230 adults aged 30~64 years. ${\chi}^2$-test and multiple logistic regressions was used for the data analysis. Results: The prevalence of hypertension among Korean middle-aged adults was 21.8% and 40.3% among participants reported that their average sleep duration was below six hours a night. Risk factors for hypertension include: female (the odds ratio (OR) 1.66 for male), 50~64 years age group (OR 3.66 for 30~49 years age group), education level of elementary school (OR 1.84 for university level), low household income (OR 1.27 for upper), obesity (OR 2.41), high risk drinking (OR 1.64), and sleep duration${\leq}6$ hrs (OR 1.16 for 8 hrs of sleep). Conclusion: High risk population of hypertension could be male, aged, low education, and low income. Obesity, high risk drinking, and short sleep duration should be considered as risk factors for hypertension. Interventions for obesity management, adequate alcohol drinking and sleep duration could be considered for preventing hypertension.

• 한국농공학회지
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• 제41권1호
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• pp.39-51
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• 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.

• Child Health Nursing Research
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• 제30권2호
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• pp.77-86
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• 2024

Purpose: This study examined the combined effects of sugar-sweetened beverage (SSB) consumption, screen-based sedentary behaviors, and sleep duration on adolescent obesity. Methods: It followed a cross-sectional study design and conducted secondary analysis on data from 20,497 high school students who participated in the 17th (2021) Korea Youth Risk Behavior Web-based Survey. This study underwent logistic regression analysis in complex sampling analysis. Results: The combinations of low and medium consumption of SSBs, excessive screen-based sedentary behaviors, and short sleep durations were associated with a 1.18 and 1.12 fold increased likelihood of obesity (95% confidence interval [CI]=1.03-1.35) and (95% CI=1.02-1.22), respectively. The combination of high SSB consumption, appropriate screen-based sedentary behaviors, and short sleep duration (adjusted odds ratio [aOR]=1.15, 95% CI=1.01-1.31) and high SSB consumption, excessive screen-based sedentary behaviors, and short sleep duration (aOR=1.40, 95% CI=1.16-1.69) were associated with obesity. Conclusion: Integrated and tailored programs considering combination patterns of SSB consumption, screen-based sedentary behaviors, and short sleep duration need to be developed for preventing adolescent obesity.