• Journal of Korea Water Resources Association
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• v.51 no.9
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• pp.747-759
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• 2018

Multivariate regional frequency analysis has advantages of regional and multivariate framework as adopting a large number of regional dataset and modeling phenomena that cannot be considered in the univariate frequency analysis. To the best of our knowledge, the multivariate regional frequency analysis has not been employed for hydrological variables in South Korea. Applicability of the multivariate regional frequency analysis should be investigated for the hydrological variable in South Korea in order to improve our capacity to model the hydrological variables. The current study focused on estimating parameters of regional copula and regional marginal models, selecting the most appropriate distribution models, and estimating regional multivariate growth curve in the multivariate regional frequency analysis. Annual maximum rainfall and duration data observed at 71 stations were used for the analysis. The results of the current study indicate that Frank and Gumbel copula models were selected as the most appropriate regional copula models for the employed regions. Several distributions, e.g. Gumbel and log-normal, were the representative regional marginal models. Based on relative root mean square error of the quantile growth curves, the multivariate regional frequency analysis provided more stable and accurate quantiles than the multivariate at-site frequency analysis, especially for long return periods. Application of regional frequency analysis in bivariate rainfall-duration analysis can provide more stable quantile estimation for hydraulic infrastructure design criteria and accurate modelling of rainfall-duration relationship.

• The Korean Journal of Community Living Science
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• v.16 no.1
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• pp.49-58
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• 2005

The purpose of this study was to identify the eating habits and attitudes by socioeconomic factors(sex, age, educational level and annual family income) of adults in rural areas. The survey was administered by the nationwide 580 adult persons in rural in February 2001. The survey was conducted by a questionnaire that was composed of 20 items of likert-type scale. These data were analyzed by using SPSS(version 10.0) PC package and were expressed by mean and frequency. The results are following : 1) The degree of efforts to eating safe and fresh food were significantly different according to age(p<0.05), educational level(p<0.001) and annual family income(p<0.001). 2) The degree of efforts to nutritional balanced diet were significantly different by age(p<0.05) and annual family income(p<0.00l). 3) The concern about overeating of energyㆍsaltㆍfat were increased as the educational level goes up(p<0.001). 4) Meal regularity was more regular as age goes up(p<0.05). 5) Regarding for eating a variety of food were differed significantly by age(p<0.05) and educational level(p<0.01). 6) There are significantly different in duration of meal time of the subjects by sex(p<0.001), age(p<0.05) and educational level(p<0.0l). 7) Preference for snacks was significantly different by age (p<0.05) and educational level(p<0.0l). 8) There were significant differences in preference for processed foods(p<0.001) and frequency of using a chemical seasoning in cooking(p<0.05) of the subjects by educational level. 9) As the age(p<0.001) goes up and the educational level(p<0.001) and annual family income(p<0.001) goes down, they did not recognize the necessity for improving eating habits. According to these results, there were differences in eating habits between socioeconomic characteristics group in rural area. Therefore, this study can be used as basic data for specific nutritional intervention program in rural areas.

• Bulletin of the Korean Space Science Society
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• 2004.04a
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• pp.36-36
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• 2004

Ionospheric data from DGS-256 ionosonde operated by Radio Research Laboratory in Anyang archived during 1991-2002 was extracted and analyzed firstly in Korea. Daily, monthly and annual variations of the 12-year F2 layer critical frequency(foF2) are derived to investigate the statistical ionospheric characteristics during one complete solar cycle. Positive correlation between the mean values of 24-hourly monthly median foF2 and the monthly smoothed sunspot number(SSN) for the same period is found. (omitted)

• Journal of Korea Water Resources Association
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• v.41 no.2
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• pp.163-172
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• 2008

Hydrologic regimes play a major role in determining the biotic composition, structure, and function of river ecosystem. In this study, hydrologic regimes were analyzed on down stream effects of the Young-Chun dam construction using the Indicators of Hydrologic Alterations(IHA). The analysis results were as follows ; (1) Monthly mean flows were decreased during drought and flood season on the pre and post dam, (2) Magnitude and Duration of Annual Exterm Conditions, annual minima 1-day means was $3.48m^3/sec$, $0.89m^3/sec$ and annual maxima 1-day mean was $833.1m^3/sec$, $672.1m^3/sec$ on the pre and post dam (3) Timing of Annual Exterm conditions, Julian date of the annual minima 1-day means was 180th(June) in the pre dam, 257th(September) in the post dam, Julian date of the annual maxima 1-day means was 209th(July) in the pre dam, 217th(August) in the post dam, (4) Frequency and Duration of High and Low Pulse, Low Puls counts and duration were 3 times and 23 days in the pre dam, High Pulse counts and duration were 4 times and 2 days in the pre dam. (5) Rate and Frequency of Water Condition Changes, rise rates was 39.27 %, 19.36 % and fall rates -15.85 %, -8.16 % in the pre and post dam, respectively (6) Coefficient of Variation, annual exteram water conditions were decreased from 0.9054 to 0.6314 and from 1.0440 to 0.9617, Timing of Annual Exterm conditions were incereased for minima flow from 0.269 to 0.282, for maxima form 0.069 to 0.153.

• The Korean Journal of Ecology
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• v.17 no.4
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• pp.513-521
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• 1994

Distribution patern of 30 species that are occurring predominantly in the mantle communities (Mantelgesellschaften) in South Korea was studied. The study was arried out by geographic and bioclimatic analysis on 368 releves obtained from the Zurich-Montpellier School's method, which involves direct analysis on the latitude, altitude, annual mean temperature and the lowest temperature of the site. Rosa multiflora and Pueraria thunbergiana which are regarded as repersentative pioneer species to the mantle community has the highest frequency, 70.1% and 60.3%, respectively. Three distribution patterns were recognized, i.e. northern type, central type and southern type, and each type was characterized by horizontal and altitudinal amplitude. Their concetrate distribution ranges on the annual mean temperature were 8~11℃, 9~12℃ and 10~13℃, respectively. It was recognized that tendencies of overlapping and continuous distribution pattern of the types and species exist. Geographically, the souther limit f the northern type is 35.5。N and the northern limit of the southern type 37.0。N. The central type is located at an coincided with the previous study in which cool-temperate forests were synchorologically indentified into northern/altimontane, certral/montane and southern/submontane type. The subsidiary knowledges from this study will provide practical information on the constructuin of the fence plant community for environmental conservation.

• Journal of The Korean Society of Clinical Toxicology
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• v.14 no.2
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• pp.122-128
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• 2016

Purpose: This study was conducted to describe the characteristics of patients with carbon monoxide (CO) poisoning. Methods: We retrospectively surveyed data from the Emergency Department based Injury In-depth Surveillance of 20 hospitals (2011-2014). We included patients whose mechanism of injury was acute CO poisoning caused by inhalation of gases from charcoal or briquettes. We surveyed the annual frequency, gender, age, result of emergency treatment, rate of intensive care unit (ICU) admission, result of admission, association with alcohol, and place of accident. We also surveyed the cause and experience of past suicide attempts by intentional poisoning. Results: A total of 3,405 patients were included (2,015 (59.2%) and 1,390 (40.8%) males and females, respectively) with a mean age of $39.83{\pm}18.51$ year old. The results revealed that the annual frequency of CO poisoning had increased and the frequency of unintentional CO poisoning was higher than that of intentional CO poisoning in January, February and December. The mean age of intentional CO poisoning was younger than that of unintentional CO poisoning ($38.41{\pm}13.03$ vs $40.95{\pm}21.83$) (p<0.001). The rates of discharge against medical advice (DAMA), ICU care and alcohol association for intentional CO poisoning were higher than for unintentional CO poisoning (36.4% vs 14.0%, 17.8% vs 4.7%, 45.2% vs 5.6%) (p<0.001). The most common place of CO poisoning was in one's residence. Conclusion: The annual frequency of total CO poisoning has increased, and unintentional CO poisoning showed seasonal variation. DAMA, ICU care, and alcohol association of intentional CO poisoning were higher than those of unintentional CO poisoning.

• Korean Journal of Ecology and Environment
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• v.48 no.4
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• pp.280-286
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• 2015

Life cycles of Sweltsa illiesi and S. lepnevae were determined from a headwater stream in Mt. Jumbong. Identification of nymphs was done by using DNA barcoding. Nymphs begin to have species specific color pattern on their head several months prior to adult emergence and differ in the form of the third antennal segment. Two species appear to have similar semivoltine life cycles in this stream, beginning to hatch from June and finishing adult emergence about 701 days later. The combined annual mean biomass in ash free dry mass (AFDM) was estimated as $96mg\;AFDM\;m^{-2}$. The combined annual secondary production were 373 mg and $297mg\;AFDM\;m^{-2}\;yr^{-1}$, calculated by using size frequency method and increment summation method respectively.

• Journal of Family Resource Management and Policy Review
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• v.16 no.4
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• pp.131-152
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• 2012

The aims of this study were to analyze middle-aged households' financial preparation for retirement. Specifically, this study surveyed the relation between human capital investment for children and the middle-aged households' financial preparation for retirement and investigated factors influencing financial preparation for retirement. Data were obtained from the 3rd Korean Retirement and Income Study (KReIS) in 2009, and a sample of 757 households was selected. The statistical methods were frequency, percentile, mean, standard deviation, ${\chi}^2$, t-test, Pearson's correlation coefficient, and logistic regression analysis. The findings of this study are as follows. First, the percentile of preparation for living costs for old age was 49.9% for the middle-aged households. In terms of the types of preparation for living costs for old age, the results showed 61.6% of personal preparation, 33.9% of pension system, and 1.3% for children and relatives. In relation to the adequacy of the preparations for living costs for old age, preparations made by 57.4% of the middle-aged households were inadequate. Observing the minimum living costs for old age and adequate living costs after retirement for single and couple, the minimum living costs of the middle-aged households was 1.46 million won for couple and 0.91 million won for single. The adequate living costs for old age was 2.07 million won for couple and 1.34 million won for single. Second, there were 757 households with total education expenditure. Of these, 208 incurred annual expenditure on public education, and the annual expenditure for public education was 7.28 million won. There were 170 households with annual expenditure for private education, and the annual expenditure for private education was 2.50 million won. 243 households of middle-aged households had annual expenditure for human capital investment, including both public and private education, with annual expenditure for human capital investment for children of 7.82 million won. Furthermore, in the human capital investment factor, there was a difference in the middle-aged households' financial preparation for retirement according to their annual expenditure for human capital investment including both public and private education. In addition, there was a difference in financial preparation for retirement based on their public education expenditure. Third, in the logistic regression model 1, which included human capital investment, the significant variables affecting the preparation for retirement of the middle-aged households were as follows : annual household income, total amount of annual household income, experience of inadequate living costs, existence of financial assets, total amount of annual household savings, financial independence, adequate living costs (for single) for old age, and human capital investment. In the logistic regression model 2, which included annual expenditure for public education and annual expenditure for private education, the significant variables affecting the preparation for retirement of the middle-aged households were as follows : annual household income, total amount of annual household income, experience of inadequate living costs, existence of financial assets, total amount of annual household savings, financial independence, adequate living costs (for single) for old age, and annual expenditure for public education.

• Ocean and Polar Research
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• v.44 no.2
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• pp.127-137
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• 2022

This study examined the growth pattern and environmental factors affecting the growth of the halophyte, Suaeda japonica, which is prevalent on tidal flats in the west coast of Korea in order to calculate annual carbon production. Quantitative sampling was conducted every month for three years from 2018 to 2020 on salt marshes located on the southern coast of Ganghwa Island. In terms of annual density affected by the germination rate at first period, especially when air temperature for winter time was constantly below 0℃ for long periods of time, germination decreased and precipitation in summer also exerted an influence. In terms of annual growth with regard to length, the part below the ground grew rapidly in the beginning after budding, while the part above ground grew at a relatively steady rate at all times. With regard to biomass, the part below the ground also increased from April in a manner similar to length growth, but decreased drastically from September with leaves falling off and water loss occurring. The part above ground showed a rapid increase from the beginning of the rainy season. Size-frequency distribution revealed broader patterns after the rainy season as individual growth varied, but from September, it stopped at all year. High growth rates were recorded in the initial phase of growth after budding and growth was rapid, but growth declined in summer when biomass increased. The annual mean production based on growth rate was calculated at 352 gDWt/m²/yr, and the highest production was 519 gDWt/m²/yr in 2018, but it has decreased since 2019. Annual carbon production was at calculated 143.41 gC/m²/yr for Suaeda japonica in the vicinity of the southern coast of Ganghwa Island.

• Journal of The Korean Society of Agricultural Engineers
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• v.51 no.4
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• pp.49-55
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• 2009

This paper is to induce design floods through L-moment with 3 and 4 parameter Kappa distributions including test of independence by Wald-Wolfowitz, homogeneity by Mann-Whitney and outlier by Grubbs-Beck on annual maximum flood flows at 9 water level gaging stations in Han, Nakdong and Geum Rivers of South Korea. After analyzing appropriateness of the data of annual maximum flood flows by Kolmogorov-Smirnov test, 3 and 4 Kappa distributions were applied and the appropriateness was judged. The parameters of 3 and 4 Kappa distributions were estimated by L-moment method and the design floods by water level gaging station was calculated. Through the comparative analysis using the relative root mean square errors (RRMSE) and relative absolute errors (RAE) calculated by 3 and 4 parameter Kappa distributions with 4 plotting position formulas, the result showed that the design floods by 4 parameter Kappa distribution with Weibull and Cunnane plotting position formulas are closer to the observed data than those obtained by 3 parameter Kappa distribution with 4 plotting position formulas and 4 parameter Kappa distribution with Hazen and Gringorten plotting position formulas.