• Title, Summary, Keyword: mean annual frequency

Search Result 133, Processing Time 0.076 seconds

Bivariate regional frequency analysis of extreme rainfalls in Korea (이변량 지역빈도해석을 이용한 우리나라 극한 강우 분석)

  • Shin, Ju-Young;Jeong, Changsam;Ahn, Hyunjun;Heo, Jun-Haeng
    • Journal of Korea Water Resources Association
    • /
    • v.51 no.9
    • /
    • pp.747-759
    • /
    • 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.

Hydrologic Regimes Analyses on Down Stream Effects of the Young Chun Dam by Indicators of Hydrologic Alterations (수문변화 지표법에 의한 영천댐이 하류하천에 미치는 유황변화 분석)

  • Park, Bong-Jin;Kim, Joon-Tae;Jang, Chang-Lae;Jung, Kwan-Sue
    • Journal of Korea Water Resources Association
    • /
    • v.41 no.2
    • /
    • pp.163-172
    • /
    • 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.

Distribution Pattern of Principal Species in the Mantle Community (임연군락의 주요종 분포양식)

  • Jung, Yong-Kyoo;Jong-Won Kim
    • The Korean Journal of Ecology
    • /
    • v.17 no.4
    • /
    • pp.513-521
    • /
    • 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.

  • PDF

Epidemiologic Characteristics of Carbon Monoxide Poisoning: Emergency Department Based Injury In-depth Surveillance of Twenty Hospitals (일산화탄소 중독의 역학적 특징: 전국 20개 병원 응급실 손상환자 표본 심층조사)

  • Bae, Sohyun;Lee, Jisook;Kim, Kyunghwan;Park, Junseok;Shin, Dongwun;Kim, Hyunjong;Park, Joonmin;Kim, Hoon;Jeon, Woochan
    • Journal of The Korean Society of Clinical Toxicology
    • /
    • v.14 no.2
    • /
    • pp.122-128
    • /
    • 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.

Research on Ionospheric Variations Associated with Solar Activity Covering One Complete Solar Cycle (1991-2002) in Korea

  • Lee, Sang-U;Kim, Jeong-Hun;Kim, Yu-Seon
    • Bulletin of the Korean Space Science Society
    • /
    • /
    • pp.36-36
    • /
    • 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)

  • PDF

Life Cycles of Sweltsa Species (Plecoptera: Chloroperlidae) in a Small Mountain Stream (산간 소하천에 서식하는 녹색강도래의 생활환)

  • Chung, Keun
    • Korean Journal of Ecology and Environment
    • /
    • v.48 no.4
    • /
    • pp.280-286
    • /
    • 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.

Factors Affecting Middle-aged Households' Financial Preparation for Retirement : Focus on Human Capital Investment for Children (중년기 가계의 노후준비에 영향을 미치는 요인 : 인적자본 투자의 영향을 중심으로)

  • Cho, Kyung-Jin;Kim, Soon-Mi
    • Korean Family Resource Management Association
    • /
    • v.16 no.4
    • /
    • pp.131-152
    • /
    • 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.

  • PDF

Estimation of Design Floods Using 3 and 4 Parameter Kappa Distributions (3변수 및 4변수 Kappa 분포에 의한 설계홍수량 추정)

  • Maeng, Seung-Jin;Kim, Byeoung-Jun;Kim, Hyung-San
    • Journal of The Korean Society of Agricultural Engineers
    • /
    • v.51 no.4
    • /
    • pp.49-55
    • /
    • 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.

A Study on the Local Climate in the Vicinity of Duckyang Bay , Korea (득량만일원의 국지기상 환경의 특성에 관한 연구)

  • 김유근
    • Journal of the Korean Society of Fisheries and Ocean Technology
    • /
    • v.28 no.4
    • /
    • pp.398-411
    • /
    • 1992
  • The characteristics of local climate in the vicinity of Duckyang Bay have been investigated with the analysis of the surface observation data of Gohug District and the aerological data of Kwangju. In principal features of local climate, the annual range in temperature appeared identical with the mean value(24~$25^{\circ}C$) of the south coastal area, and evaporation from April to September was likely less than precipitation. The average speed of surface wind in Summer seemed higher than in other seasons on account of wea breeze. Relative humidity was 74%, annual average. In the mean cloud cover Summer(6.4) showed greater deal of amount than Winter(4.2). Duration of sunshine was the longest in May(268.4hrs), while the shortest in February(188.4hrs). The amount of the precipitable water was the greatest in July, whereas the least in January, and in Summer the greatest, in Autumn the second greatest, and in Spring the third greatest, and in Winter the least in consideration of seasonal orders. The Summer deviation was most remarkable around all sides. The direction of vector wind appeared the most changeable on the earth surface. At an altitude of 300mb all the winds blew west around all months. Moreover, water vapor transport was measured to be the greatest in Summer; while the least in Winter. So was the deviation of water vapor transport. And lastly frequency of occurrence of days in which a little cloud appeared(less than 5/10) was high except for Summer, when northerly winds blew; while frequency of occurrence of day plenty of clouds floated was outstandingly high at the time of strong southerly winds.

  • PDF

Land-use Enhancement Benefit According to Flood Safety (치수안전도에 따른 토지이용의 편익 분석)

  • Lee, Jin Ouk;Kim, Hung Soo;Shim, Myung Pil;Choi, Seung An
    • Journal of Wetlands Research
    • /
    • v.6 no.4
    • /
    • pp.45-57
    • /
    • 2004
  • This study analyzed the effect of land-use enhancement benefits with the flood safety which it is not quantified in the flood damage analysis, Korea. The land-use enhancement benefits mean the enhancement of land-use value according to the rise of flood safety of the protected area by the flood control projects and we performed the analysis of land-use enhancement benefits with the publicly announced land price which can objectively represent the land-use value of a specific area. We verified the statistical significance of the floating rate of land price according to the effects of flood control projects and the characteristics of a river through the analysis of variance. As a result of the verification, the increase of land-use value was represented by the net annual average floating rate of land price. The flood safety was classified as flood damage potential and flood prevention capacity. The flood damage potential was classified according to the rate of urbanization and flood prevention capacity was represented by the conditional annual non-exceedance probability obtained from the frequency analysis with uncertainty for the flood discharge. The study areas were small urban cities and we calculated the conditional annual non-exceedance probabilities of 200-year flood event for the levees constructed with the conditions of 10- and 50-year design frequency. The result was shown that the net annual average floating rate of land price would be raised nearly 5 times for 10%-increase of the conditional annual non-exceedance probability in small city areas.

  • PDF