• Proceedings of the Korea Water Resources Association Conference
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• 2010.05a
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• pp.779-783
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• 2010

최근 들어 그 심각성을 더하고 있는 이상기후 현상으로 가용 수자원의 변동이 커지고 있으며, 이에 따라 수자원의 효율적인 운영이 요구되고 있다. 그러나 효율적인 운영을 위해서는 미래 유입량의 불확실성의 고려하고, 홍수 조절용량의 확보하면서도, 용수공급을 위한 저수량을 확보하고, 수력 발전을 해야 하는 복잡한 상황을 모두 고려하여야한다. 이러한 복잡한 시스템에서 하나의 최적화 기법으로는 모든 고려사항들을 만족시키는 최적해를 찾는 것은 사실상 불가능에 가깝다. 그러므로 저수지 운영의 최적화를 위한 연구에서 한 가지 이상의 기법을 조합하는 기법을 사용하게 되었다. 이러한 기법은 각 기법의 장점을 취하고 각각의 한계를 극복하기 위해 주로 사용되었다. 본 연구에서는 저수지 운영 최적화를 모의하기 위하여 대청댐에서의 저수위, 유입량, 용수이용량 등을 고려하여 방류량의 예측을 동적 계획법(Dynamic Programming Model)으로부터 동적 신경망(Dynamic Neural Network Model)과 적응 퍼지 제어기법(Adaptive Neuro-Fuzzy Inference System)을 개발하여 실제 방류량과 세 가지 최적화 방법에 의한 결과를 비교 검정하였다. 본 연구의 수행으로 인해 얻어진 결과를 요약하면 다음과 같다. 첫째, 동적 신경망과 적응 퍼지 제어기법에 의한 최적화 모의가 동적 계획법에 비해 시스템의 구축이 쉽고 유연하다. 둘째, 퍼지추론의 Membership 함수의 구축에 따라 단시간에 많은 양의 강우가 발생하는 국지성 강우에 대해서도 최적 방류량을 예측할 수 있다. 셋째, 저수지 운영 과거자료의 부족과 불확실성을 해결하면, 보다 용이하고 양호한 예측결과를 얻을 수 있을 것이다.

• Korean Journal of Agricultural and Forest Meteorology
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• v.12 no.2
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• pp.83-94
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• 2010

The objective of this study was to determine the best probability distributions of annual, seasonal and monthly precipitation in Korea. Data observed at 32 stations in Korea were analyzed using the L-moment ratio diagram and the average weighted distance (AWD) to identify the best probability distributions of each precipitation. The probability distribution was best represented by 3-parameter Weibull distribution (W3) for the annual precipitation, 3-parameter lognormal distribution (LN3) for spring and autumn seasons, and generalized extreme value distribution (GEV) for summer and winter seasons. The best probability distribution models for monthly precipitation were LN3 for January, W3 for February and July, 2-parameter Weibull distribution (W2) for March, generalized Pareto distribution (GPA) for April, September, October and November, GEV for May and June, and log-Pearson type III (LP3) for August and December. However, from the goodness-of-fit test for the best probability distributions of the best fit, GPA for April, September, October and November, and LN3 for January showed considerably high reject rates due to computational errors in estimation of the probability distribution parameters and relatively higher AWD values. Meanwhile, analyses using data from 55 stations including additional 23 stations indicated insignificant differences to those using original data. Further studies using more long-term data are needed to identify more optimal probability distributions for each precipitation.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.34 no.1
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• pp.117-133
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• 2014

In this study, we analysed impacts of the recent increasing trend of exceedance rainfall thresholds for separation of data set and different research periods using Quantile Regression (QR) approach. And also we performed significant test for time series data using linear regression, Mann-Kendall test and Sen test over the Korean major 8-city. Spring and summer precipitation was tend to significant increase, fall and winter precipitation was tend to decrease, and heavy rainy days in last 30 years have increased from 3.1 to 15 percent average. In addition, according to the annual ranking of rainfall occurs Top $10^{th}$ percentile of precipitation for 3IQR (inter quartile range) of the increasing trend, most of the precipitation at the point of increasing trend was confirmed. Quantile 90% percentile of the average rainfall 43.5mm, the increasing trend 0.1412mm/yr, Quantile 99% percentile of the average rainfall 68.0mm, the increasing trend in the 0.1314mm/yr were analyzed. The results can be used to analyze the recent increasing trend for the annual maximum value series information and the threshold extreme hydrologic information. And also can be used as a basis data for hydraulic structures design on reflect recent changes in climate characteristics.

• Journal of Digital Convergence
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• v.15 no.12
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• pp.517-529
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• 2017

The purpose of this study is to develop and evaluate the scale for university students' health behaviors. This research is based on Roger's(1975) Protection Motivation Theory and Weinstein(1988)'s Precaution Adoption Process Model as theoretical frameworks. The contents of the scale were first abstracted from personal depth interviews of qualitative study on university students' health behavior experiences and review of its related literature. The initial items consisted of 76 behavior questions and 34 perception questions. After conducting the preliminary test, 33 behavior questions and 24 perception questions were selected for the final test by revisions on the basis of the result of the content validity test and the item understanding test. The questionnaires for the final test were distributed to 400 students enrolled in three universities. The questionnaires collected from 373 participants were analyzed by the SPSS program. From the examination of construct validity, item correlation, and factor relation turned out to be relevant. Five factors were determined from 27 items with a cumulative explained variance of 54.498 %. After examining reliability and validity of the collected dat, 27 items were finalized as the scale for university students' health behaviors.

• Journal of Korea Water Resources Association
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• v.55 no.4
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• pp.257-266
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• 2022

Inundation damage is increasing every year due to localized heavy rain and an increase of rainfall exceeding the design frequency. Accordingly, the importance of hydraulic structures for flood control and defense is also increasing. The hydraulic structures are designed according to its purpose and performance, and the amount of flood is an important calculation factor. However, in Korea, design rainfall is used as input data for hydrological analysis for the design of hydraulic structures due to the lack of sufficient data and the lack of reliability of observation data. Accurate probability rainfall and its temporal distribution are important factors to estimate the design rainfall. In practice, the regression equation of temporal distribution for the design rainfall is calculated using the cumulative rainfall percentage of Huff's quartile method. In addition, the 6^th order polynomial regression equation which shows high overall accuracy, is uniformly used. In this study, the optimized regression equation of temporal distribution is derived using the variable selection method according to the principle of parsimony in statistical modeling. The derived regression equation of temporal distribution is verified through the significance test. As a result of this study, it is most appropriate to derive the regression equation of temporal distribution using the stepwise selection method, which has the advantages of both forward selection and backward elimination.

• Journal of Digital Convergence
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• v.14 no.2
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• pp.501-507
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• 2016

We obtained medical test data of 150 male from National Health Insurance Corporation, that included physique, blood chemistry, and lifestyle. ${\chi}^2-test$ and logistic regression, and multiple regression were done to verify how CAD risks and/or lifestyle are different between obese and non-obese person. SPSS(version 18) was used for statistical procedures and p-value of .05 was regarded as good through. ${\chi}^2-test$ showed the frequency of hypertension, htperglycemia, hyperlipidemia were higher in obese person than in non-obese This result told us that lifestyle modification could be a key to prevent cardiovascular disease by controlling and managing body composition, especially abdominal obesity.

• The Journal of the Korea Contents Association
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• v.11 no.12
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• pp.335-346
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• 2011

The aim of this study is to compare the differences of influencing factors and subjective digestive symptoms among upper gastrointestinal disease groups. Subjects of this study are the results of Helicobactor Pylori test, gastrofibroscopic findings, and the electronic data of medical questionnaires on individuals at the age of 20 to 79 who visited a Health Promotion Center in Seoul from October, 2003 to October, 2004. 2,708 cases are analysed for final with $x^2$ test and ANOVA test. The sociodemographic factors of sex, age and occupation, the living habits factors of smoking and drinking, the pathophysiological factor of H. pylori infection, and the psychological factor of stress show statistically significant differences among groups. The digestive symptoms of "the feeling of something remained in the stomach", "the burning feeling right after eating or at the empty state of stomach" and "the frequent reflux of watery acid from the stomach" show statistically significant differences among groups. This study provides meaningful data in finding distinctive features of each disease and will be applied as basic materials to the development of intervention methods for health promotion relating to the upper gastrointestinal diseases.

• Proceedings of the Korea Water Resources Association Conference
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• 2017.05a
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• pp.408-408
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• 2017

기후변화에 따른 극한 기후의 시 공간적 변동성과 패턴의 이상변화가 가속화되고 있으며, 이에 따른 물 순환 특성의 변화는 이수, 치수, 환경 그리고 친수 등 다양한 분야에서도 예측할 수 없는 결과를 초래하고 있다. 특히, 치수 및 이수 등 국내 수자원 관리의 대부분을 담당하고 있는 다목적댐 운영에서도 기후변화에 따른 유입량의 불확실성 증가로 안정적인 용수공급에 대한 어려움이 점차 증가하고 있는 추세이다. 유역 내의 수문학적 반응은 기상 및 지표 수문 인자의 물리적 상호메카니즘에 의해 발생하게 된다. 특히, 강우, 기온, 습도, 바람 등 기상학적 인자들은 유역 내의 수문 변동성에 직 간접적으로 영향을 주는 대표적인 인자이며, 이들 기상인자의 변동 특성을 반영하기 위한 기후지수(Climate Index, CI)는 지표수문인자인 유출과의 상관관계 분석에 유용하게 활용될 수 있다. 본 연구에서는 낙동강 유역 다목적댐을 대상으로 AR5 RCP 시나리오 기반의 기상인자에 대한 기후지수(CI)를 산정하고 다목적댐 유입량과의 상관성을 분석하였다. 대상유역의 기상 및 유입량 관측자료(1976-2005)는 기상청과 국가수자원관리종합정보시스템(WAMIS)를 이용하였으며, AR5 RCP 시나리오 기반의 유입량 자료(2005-2099)는 통계적 기법(QDM)으로 상세화된 기상자료를 입력인자로 수문모형(PRMS)을 통해 산정하였다. 또한, 기후지수(CI)와 유출지수(Standardized Streamflow Index, SSI)의 상관성 분석을 위해 Pearson 적률상관 분석방법을 적용하였으며, 통계적 유의성 검증은 Student t 검정방법을 적용하였다. 본 연구의 방법론과 결과는 기후변화에 따른 다목적댐 안정적인 용수공급을 위한 다양한 기술개발 시 기초자료로 활용될 수 있을 것으로 기대된다.

• Journal of Digital Convergence
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• v.13 no.1
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• pp.375-382
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• 2015

The purpose of this study was to investigate the factors related to problem drinking in male workers according to occupational classes. Data were derived from the 2012 Korean National Survey on male workers. A total of 391 office workers, 707 manufacturing workers, and 309 service workers participated in this study. Data were analyzed using Rao-Scott $X^2$-test, simple and multiple logistic regressions. Problem drinking was defined as ${\geq}8$ points in the Alcohol Use Disorders Identification Test. The problem drinking rates were 45.1% in office workers, 39.1% in manufacturing, and 42.3% in service. In office workers, the factor related to problem drinking was only smoking. In manufacturing workers, the factors related to problem drinking were spouse, smoking and prevalence of Diabetes. In service workers, the factors related to problem drinking were age and smoking. Therefore, different intervention should be developed for each occupational class in order to manage the problem drinking in male workers.

• Culinary science and hospitality research
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• v.20 no.3
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• pp.64-79
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• 2014

This study was conducted to examine changes in coffee intake according to the sociodemographic characteristics of the people over 50 and the elderly living in Korea. The data of 2,316 and 3,170 people were extracted respectively from the 2001 and 2011 Korea National Health and Nutrition Examination Surveys. The data were analyzed by gender, age, region area, marital status, educational level, household income, economic activity, and subjective health status. They were also analyzed according to gender and age by average daily intake of coffee, coffee type, place, cups of coffee a day and amount of coffee intake per serving. All statistical analyses were performed with IBM PASW Statistics (SPSS) 21.0 which is capable of complex sample design by frequency analysis, chi-square test, t-test, and logistic regression analysis. The results of the study showed that coffee consumption of the elderly was influenced by their economic activity. In 2011, elderly men ingested averagely more coffee than elderly women, and they also consumed brewed coffee mostly at workplace. Moreover, age groups of over 75 tended to consume a lot of brewed coffee. In this respect, the coffee industry should be aware of the elderly as a new consumption group. Also, this study provides a variety of coffee shops with basic data for product development and marketing activities.