• Proceedings of the Korea Water Resources Association Conference
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• 2012.05a
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• pp.347-351
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• 2012

본 연구는 기후변화로 인한 국내 낙동강 유역의 기온, 강수, 상대습도의 변동 경향을 파악하고자, 낙동강 본류의 상, 중, 하류 지역을 연구대상 지역으로 선정하여 분석을 실시하였다. 이를 위하여 기상요소인 평균, 최저, 최고 기온과 상대습도 및 강우 자료를 기상청의 관측 자료를 활용하여 수집하였다. 분석을 실시함에 있어서 연평균, 최고, 최저 기온과 연평균, 최고, 최저 상대습도를 분석하였으며, 강우량 관측 자료를 통해 총 강우량, 강우집중률, 일 최대강우량을 고려하였다. 분석방법은 기후변화로 인한 기상자료의 변동 경향을 파악하기 위하여 비모수적 경향성 검정인 Mann-Kendall Test, Hotelling-Pabst Test, Sen's Test 3가지의 검정방법을 사용하였으며, 표준정규변량의 크기를 통하여 변동 경향의 유의성을 비교해보았다. 또한, 각 요소별 관측 자료의 상위 10개, 하위 10개의 자료를 통하여 최근(1995~2011)과 과거(1973~1994)의 기상요소들을 비교하여 변동 특성을 파악하였다. 연구지역 중 낙동강 중류 지점에 위치하는 구미의 경우, 요소별 자료 중 연평균기온의 상위 9개의 자료가 최근 17년 이내에 포함되어 있으며, 연 최저 및 최고 기온의 6개의 자료가 포함되어 있어 기후온난화가 진행되고 있음을 확인하였다. 연 최저 상대습도의 경우 3가지 경향성 검정 방법을 통하여 과거자료에 비해 하강하는 추세를 보이고 있다. 강우자료 분석 결과 관측이 시작된 이래 연강수량 중 상위 10개의 자료에서 7개가 최근에 발생한 것으로 분석되었고, 일 최대강우량은 9개가 포함되어 있다. 위의 요소별 분석 결과 낙동강 유역의 연강수량 및 강우강도는 대체적으로 증가하고, 기온 또한 증가하는 등 기후 변화로 인한 지구온난화현상이 국내에서도 나타나는 것을 확인 할 수 있었다.

• Proceedings of the Korea Water Resources Association Conference
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• 2004.05b
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• pp.719-723
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• 2004

본 연구에서는 일 최고, 최소치 유출량 계열을 확충하기 위해 ARIMA(p,d,q) 모형을 이용하였으며, 분석 자료의 경향성 유무를 파악하기 위해 Mann-Kendal 비모수적 검정을 실시하였다. 분석 결과, 최고 최소 유출량 자료 모두 경향성이 없는 것으로 분석되었다. ARIMA(p,d,q) 모형의 최적 차수를 결정하기 위해 ACF, PACF, AIC, 그리고 SBC(Schwarz Bayesian Criterion) 검사를 실시하였으며 이를 통해 최적의 ARMA 모형을 결정하였다. 일 최대치 자료의 경우 추계학적 경향 보다는 무작위적 특성을 보였으며, 일 최소치 자료계열 경우, ARMA(1,0) 모형이 최적 모형으로 선정되었다.

• Journal of Korean Society for Atmospheric Environment
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• v.7 no.3
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• pp.180-188
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• 1991

기후변화를 나타내는 연구 결과들은 기온이나 강수량을 대상으로 하여 두 기간 평균치의 비교, 5년 이동평균치의 圖示, 회귀분석 등의 방법들을 사용하여 발표되지만 대부분의 경우 밑바탕이 되는 모집단의 통계적 특성을 엄격히 검토하지 않는 정성적인 분석인 경우가 많다. 서울, 부산, 인천, 목포 등 4개 지점의 80년 동안의 연강수량과 연평균기온자료를 분석한 결과 기온은 정규분포를 나타내므로 전통적인 t-검정과 회귀분석을 적용할 수 있다. t-검정 결과 두 기간(1920 $sim$ 1949, 1961 ~ 1990)은 연평균기온에서 0.3$^{\circ}$C에서 $0.8^{\circ}$C의 의의있는 차이를 보였다. 최근 30년의 연평균기온자료를 회귀분석한 결과 1년에 $0.02^{\circ}$C의 증가경향을 나타내었다. 연강수량은 정적인 왜곡도를 보이므로 정규분포를 가정하는 母數的 통계분석을 적용해서는 안되며 비모수적 통계분석법을 적용해야 한다. 연강수량의 분석에는 t-검정에 상응하는 Mann-Whitney 검정을 적용해 본 결과 두 기간(1920 ~ 1949, 1961 ~ 1990)의 평균은 통계적으로 의의있는 차이가 없었다. 회귀분석에 상응하는 Mann's 검정과 이 연구에서 새로이 제안된 Median Slope Change Estimator를 적용해 본 결과 역시 통계적으로 의의있는 변화가 없었다. Median Slope Change Estimator는 비모수적 통계치로서 회귀분석의 기울기에 해당하는 연변화를 나타낼 수 있는데 분석하려는 자료의 정규분포성을 요구하지 않으며 異常點(outlier) 영향에 덜 민감하다는 장점이 있으므로 주목하여 연구할 만한 가치가 있다.^{\circ}$~40$^{\circ}$ 구간에서는 ${\sigma}_c$와 I$_{sa}$, 40$^{\circ}$~90$^{\circ}$ 구간에서는 ${\sigma}_c$와 I$_{sd}$가 각각 양호한 상관관계를 보여준다. 또한 상관비(K=${\sigma}_c$/I$_s$)는 약 13정도로서 일반적으로 적용되는 비, 24와 상당한 차이가 있다. 이러한 현상은 호상편마암의 구조적 및 역학적 이방성 특성으로 인한 결과라고 판단된다. 한편 맥암류에서 K가 약 23정도로서 일반적인 비 24에 상당히 접근한다. 따라서, 이방성 구조가 뚜렷한 암석에서 상관비 24는 항상 적용할 수는 없으며 일축압축강도시험과 병행 실시하여 적용하는 것이 바람직하다.다. 한편, 감작감염후 77일과 도전감염후 7일의 시점에 있어서 sRBC에 대한 면역능에 미치는 영향은 전자의 양상과 비슷하였는데 대조에 비하여 지연형 과민반응과 로제트 형성능이 현저하게 저하되었다. 이 시점에 있어서의 유충회수율은 대조가 10.5% 이었는데 비하여 8.3%이었다.e also compared for the cases of Kim et al, which again gives promising agreement.면적 306~453$\textrm{cm}^2$, 유색계의 경우 수당면적 340~453$\textrm{cm}^2$ 일 때 경제능력을 제대로 발휘할 수 있고 경제성이 있는 것으로 나타났다. 첨가구가 높은 경향이 있었다8.4%. 79.7% 그리고 80.2%였다.

• Journal of Korean Society for Atmospheric Environment
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• v.19 no.1
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• pp.93-100
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• 2003

In this technical information, the long-term measurement data at Gosan between 1992 and 2001 are analyzed with various statistical methods. First. it was confirmed that the basic assumption of t-test is important to classify data correctly. Second, it was founded that the difference of the number of data per month can affect the averaged concentration. Third, by using a non-parametric statistical method long term trend of aerosol composition free from seasonal effects is obtained.

• Journal of Korea Water Resources Association
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• v.47 no.9
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• pp.753-766
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• 2014

The future mean sea level rise (MSLR) due to climate change in major harbors of Korean Peninsula has been estimated by some statistical methods in this article. Firstly, Mann-Kendall non-parametric trend test to find some trend in the observed long-term tidal data has been performed and also Bayesian change point analysis has been used also to detect the location of change points and their magnitude quantitatively. Especially, in this study, the results from Bayesian change point analysis have been applied to combine 4 future MSLR scenario projections with local MSLR data at 5 tidal gauges. This proposed procedure including Bayesian change point analysis results can improve the step for the determination of starting years of future MLSR scenario projections with 18.6-year lunar node tidal cycle and effectively consider local characteristics at each gauge. The final results by the proposed procedure in this study have shown that the future MSLR in Jeju region (Jeju tidal gauge) is in the largest increment and also the future MSLRs in Western region (Boryeong tidal gauge) and Southern region (Busan tidal gauge) are in the second largest one. Finally, it has been shown that the future MSLRs in Southern region (Yeosu tidal gauge) and Eastern region (Sokcho tidal gauge) seem to be in the relatively smallest growth among 5 gauges.

• Journal of Korea Port Economic Association
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• v.31 no.1
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• pp.1-14
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• 2015

The standard GARCH model imposing symmetry on the conditional variance, tends to fail in capturing some important features of the data. This paper, hence, introduces the models capturing asymmetric effect. They are the EGARCH model and the GJR model. We provide the systematic comparison of volatility models focusing on the asymmetric effect of news on volatility. Specifically, three diagnostic tests are provided: the sign bias test, the negative size bias test, and the positive size bias test. This paper shows that there is significant evidence of GARCH-type process in the data, as shown by the test for the Ljung-Box Q statistic on the squared residual data. The estimated unconditional density function for squared residual is clearly skewed to the left and markedly leptokurtic when compared with the standard normal distribution. The observation of volatility clustering is also clearly reinforced by the plot of the squared value of residuals of export volume and values. The unconditional variance of both export volumes and export value indicates that large shocks of either sign tend to be followed by large shocks, and small shocks of either sign tend to follow small shocks. The estimated export volume news impact curve for the GARCH also suggests that $h_t$ is overestimated for large negative and positive shocks. The conditional variance equation of the GARCH model for export volumes contains two parameters ${\alpha}$ and ${\beta}$ that are insignificant, indicating that the GARCH model is a poor characterization of the conditional variance of export volumes. The conditional variance equation of the EGARCH model for export value, however, shows a positive sign of parameter ${\delta}$, which is contrary to our expectation, while the GJR model exhibits that parameters ${\alpha}$ and ${\beta}$ are insignificant, and ${\delta}$ is marginally significant. That indicates that the asymmetric volatility models are poor characterization of the conditional variance of export value. It is concluded that the asymmetric EGARCH and GJR model are appropriate in explaining the volatility of export volume, while the symmetric standard GARCH model is good for capturing the volatility.

• Journal of Animal Science and Technology
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• v.53 no.5
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• pp.397-408
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• 2011

The study was carried to identify the impact on nation-wide genetic evaluation and to obtain basic materials for the development of strategies in Swine Improvement Network Project (SINP). Data consisted of pedigree records of 235,511 and performance records of 70,747 for Duroc from 1987 to 2010 were collected by Korea Animal Improvement Association. Performance traits included three point back fat thickness (Shoulder, Belly, Waist), loin area, days to 90 kg and average daily gain. Exchange of genetic resources cross the breeding farms was not high, and furthermore the sizable farms which can accommodate genetic evaluation within the farm were scarce. Three data sets (individual farm evaluation: I, two sub-group evaluation: S, and whole eight farm evaluation: P) were used for genetic analysis. Genetic variances were larger in subordinate farms than in joiners farms for connectedness, and consequently the heritabilities were generally higher in subordinate farms than in joiner farms with I. The standard errors of heritability were small in the order of I, S and P. Estimated average inbreeding coefficients were 1.12%, 0.95% and 1.53% for joiner and subordinate group with S and population with P, respectively. The estimated correlations of breeding values with I and P were lowest. The correlations of breeding values with I and P for traits ranged 0.22 to 0.45 for moved parent animals and 0.24 to 0.72 for all animals. The results in the study suggest that nation-wide evaluation uses more pedigree information and improves accuracy. Furthermore SINP for connectedness could help to improve the accuracy of evaluation.

• Journal of the Korean Society of Radiology
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• v.14 no.5
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• pp.537-543
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• 2020

The elderly population in the modern society is growing rapidly due to advance medical technology and minimally invasive surgery. Therefore, as the tendency to use medical device is increasing, pathogenic infection is a concern. Therefore, the first aim of modern medicine is infection prevention in medical place. Recently, patient implants are increasing using 3D printing. Hydroxyapatite is used as a representative material. And, there haven't had currently absorbed dose standard for sterilization of hydroxyapatite discs. Escherichia coli and Streptococcus mutans contaminated on the surface of hydroxyapatite discs were irradiated at each absorbed dose of 0, 0.5, 1.0, 3.0, 5.0 kGy using Gamma-ray of cobalt and Electron-beam of linear accelerator. Then, the number of bacteria was measured in the sample by the decimal dilution method. After sterilization, a non-parametric testing method was performed to compare the survival of Escherichia coli and Streptococcus mutans. As a result, Escherichia coli was sterilized at 1 kGy or more and Streptococcus mutans at 3 kGy or more on absorbed dose. It is considered possible to perform sterilization at a lower value than the recommended absorbed dose of radiation sterilization.

• Korean Journal of Psychosomatic Medicine
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• v.22 no.2
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• pp.121-129
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• 2014

Objectives : This study was to assess the prevalence and its correlates of restless legs syndrome(RLS) in outpatients with bipolar disorder. Methods : A total of 100 clinical stabilized bipolar outpatients were examined. The presence of RLS and its severity were assessed using the International Restless Legs Sydrome Study Group(IRLSSG) diagnostic criteria. Beck's Depression Inventory(BDI), Spielberg's State Anxiety Inventory(STAI-X-1), Pittsburgh Sleep Quality Index(PSQI), Korean version Drug Attitude Inventory(KDAI-10), Subjective Well-Beings under Neuroleptic Treatment Scale-Short Form(SWN-K) and Barnes Akathisia Rating Scale(BARS) were used to evaluate the depressive symptomatology, level of anxiety, subjective quality of sleep, subjective feeling of well-being, drug attitude, presence of akathisia, respectively. Results : Of the 100 bipolar outpatients, 7(7%) were met to full criteria of IRLSSG and 36(36%) have at least one of the 4 IRLSSG criterion. Because of relatively small sample size, non-parametric analysis were done to compare the characteristics among 3 groups(full-RLS, 1 ${\geq}$positive RLS-symptom and Non-RLS). There were no significant differences in sex, age, and other sociodemographic and clinical data among 3 groups. BDI, STAI-X-1 and PSQI are tended to be impaired in RLS and 1 ${\geq}$positive RLS-symptom groups. Conclusions : This is the first preliminary study for studying the prevalence and its correlates of RLS in bipolar disorder. The results shows that relatively small proportion of RLS was present in bipolar disorder patients when compared to patients with schizophrenia. Same tendencies shown in schizophrenic patients were found that bipolar patients with RLS had more depressive symptoms, state anxiety and poor subjective sleep quality. Further systematic studies may be needed to find the characteristics of RLS in bipolar patients.

• Journal of Korea Port Economic Association
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• v.32 no.3
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• pp.35-46
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• 2016

This study investigates the export behavior of Busan, Gwangyang and Incheon Port. The monthly data cover the period from January 2000 to December 2015. We employ six export functions composed of various exchange rates and industrial production index. This paper finds that the nominal effective exchange rate is more appropriate for explaining the export behaviors of the three ports, regardless of the narrow and wide indices which comprise 26 and 61 economies for the nominal and real indices respectively. This paper tests whether exchange rate and industrial production are stationary or not, rejecting the null hypothesis of a unit root in each of the level variables and of a unit root for the residuals from the cointegration at the 5 percent significance level. The error-correction model is estimated to find that both Gwangyang and Incheon ports are much slower than Busan port in adjusting the short-run disequilibrium and Gwangyang port is a little slower than Incheon port. The rolling regressions show that the influence of exchange rate as well as industrial production tends to decrease in all of three ports. The variance decomposition, however, shows that the export variables are very exogenous and the export of Busan Port is the least exogenous and that of Gwangyang Port the most. This result indicates that the economic variables such as exchange rate and economic activity affect the export of Busan Port more strongly than that of Gwangyang and Incheon Port.