• Proceedings of the Korea Water Resources Association Conference
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• 2005.05b
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• pp.567-570
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• 2005

본 연구에서는 GEV분포형에 패해 L-모멘트법을 적용하여 추정된 지점빈도 설계강우량의 변동추이가 관측년수변화에 따라 어떠한 변동추이를 나타내는지를 규명함으로써 향후 수리시설물의 설계방향모색에 도움이 되고자 한다. 현재 우리나라는 수리시설물의 설계나 관리시에 PMP, PMF 또는 빈도별 설계수문량 등을 이용하고 있다. 그러나, 이러한 수문량들은 매년 관측되는 수문관측치들에 의해서 매번 변하고 있으며 또한 이러한 변화의 양상과 크기는 각 지점별로 매우 다양하게 나타나고 있다. 이로인해, 수리시설물의 설계 및 관리시 관측 지점별로 매우 상이한 설계수문량을 제시하기도 하며 특정관측자료로 인해 설계수문량이 급변하는 등 많은 혼란을 초래하고 있는 실정이다. 따라서, 현재 관측지점별로 나타나고 있는 설계수문량의 변화양상을 분석함으로써 추후에 변화될 설계수문량의 양상 예측이 가능할 것으로 판단된다. 본 연구는 우리나라 전역에 걸쳐 기록년수가 가장 긴 강릉, 서울, 인천, 추풍령, 포항, 대구, 전주, 울산, 광주, 부산, 목포 및 여수기상대의 총 12개소를 선정하여 해당 기상대의 24시간 최대강우량을 대상으로 지점빈도분석을 실시한다. 지점빈도분석시 적용된 분포형과 매개변수추정법은 최근 가장 많이 사용되고 있는 GEV분포형과 L-모멘트법을 적용한다. 또한. 최종결론은 설계수문량의 양상을 형태별로 분류하고 형태에 따른 특성들과 예상되는 현상들에 대해 기술하고자 한다.

• Journal of the Korea Computer Industry Society
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• v.6 no.3
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• pp.495-508
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• 2005

Moving objects are spatiotemporal data that change their location or shape continuously over time. Their location coordinates are periodically measured and stored i3l the application systems. The linear function is mainly used to estimate the location information that is not in the system at the query time point. However, a new method is needed to improve uncertainties of the location representation, because the location estimation by linear function induces the estimation error. This paper proposes an application method of the cubic spline interpolation in order to reduce deviation of the location estimation by linear function. First, we define location information of the moving object on the two-dimensional space. Next, we apply the cubic spline interpolation to location estimation of the proposed data model and describe algorithm of the estimation operation. Finally, the precision of this estimation operation model is experimented. The experimentation comes out more accurate results than the method by linear function.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2004.11a
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• pp.111-116
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• 2004

In this paper, parameters of a given DC motor system are estimated using the model adjustment technique and the real coded genetic algorithm(RCGA) technique. A number of tuning methods, based on experience and experiment, such as Ziegler-Nichols, Cohen-Coon, IMC, L-ITAE Method have been proposed to obtain parameters for the PID controller. This paper proposes estimating parameters of PID controller using RCGA. The performance of the proposed algorithm is demonstrated through simulations and experiences.

• Magazine of the Korean Society of Agricultural Engineers
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• v.38 no.1
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• pp.90-97
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• 1996

In Korea, total sediment discharge of a river has been estimated simply by using certain sediment transport formulas including, among others, Einstein's formula. Those formular, however, are known not to be reliable enough for the result calculated by them to be used directly to river planning and management. Therefore, the study used the Modified Einstein Procedure to the estimation of total sediment discharge, because this method is reliable estimated by measurement. Here, measurement of sediment discharge used depth integrating method. The major results obtained from the study for estimation by depth integrating method of sediment discharge in Naeseong stream are as follow; 1 The sedeiment characteristics of Naeseong stream are; The distribution of sediment grain size shows that silt and clay are 55% and sand is 45%. and the bed load sediment grain size is constituted that sand contained with the grain size from O.062mm to 2.0mm is 80% 2. The sediment rating formulas derived from the regression analysis between the sediment discharge and flow discharge are; Seogpo-Gyo : Qs=$0.017 \times 10^{-4} Q^{2.352}$, where discharge is l0cms $0.074 \times 10^{-4} Q^{2.066}$, where discharge is l0cms

• Proceedings of the Korea Water Resources Association Conference
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• 2011.05a
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• pp.332-332
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• 2011

하천 유사량 특성 분석은 하천유역 내의 수리구조물 설계 및 유지관리, 하천개수 및 하도의 안정, 홍수터 관리, 저수지 설계 및 운영 등 수자원 개발 및 관리를 위한 하천계획의 필요한 요소 중 하나이며 현장 측정에서 분석까지 정밀한 일련의 과정을 통해서 알아낼 수 있다. 본 연구에서는 6개 지점(여주, 왜관, 진동, 공주, 나주, 구례2)에 대해 유사량 특성 분석을 수행하였다. 부유사량은 강우가 집중되는 홍수기(왕복수심적분법; D-74측정장비 / 표면채취법)를 중심으로 측정하였고 하상토의 경우는 Grab Sampler(60L), 선격자법 등을 이용하여 홍수기 전 후로 2회 채취하였다. 채취된 시료는 특성에 따라 여과법(부유사농도), BW관법(부유사입도분포), 체분석법(하상토입도분포)으로 분석하였으며, 이를 통해 산정된 평균 부유사농도, Oden Curve와 입도분포곡선 및 수리량(수위, 유속, 측정수심, 수면폭, 수면경사, 수온)등의 자료를 이용하여 총유사량(Modified Einstein 방법)을 추정하였다. 본 연구 결과는 다음과 같다.: 1) 유량-부유사량 및 총유사량 관계: 유량-부유사량의 관계에 있어 대체적으로 일관된 경향성이 나타났으며 총유사량과의 관계 역시 부유사량과 비슷한 경향성을 보임. 일부 성과의 경우, 총유사량과의 관계에 있어 Modified Einstein 조건의 불충족(자갈하상재료 또는 저유속)으로 부유사량과 동일추정이거나 추정불가 및 이상치가 나타남. 2) 유량-부유사량 특성: 전체적으로 루프현상을 보이며 초기 강우 사상에서는 더 많은 유사량이 발생하는데 이는 초기 강우에 의해 유사 이송이 활발하게 이루어지는 일반적인 특성임. 또한 수위 상승-하강에 따른 부유사량 자료가 더욱더 확보된다면 수위 상승과 하강부로 구분하여 분석하는 것도 의의가 있을 것으로 판단됨. 3) 유량-유사량관계식 개발: 개발된 관계식은 총유사량이 아닌 부유사량으로 개발되었으며, 측정성과들 간의 상관계수가 0.9723(구례2 지점) ~ 0.8490(나주 지점)으로 분석됨. 또한 개발된 관계식에 대한 신뢰도 분석을 실시하지 않았기 때문에 적용 시에는 주의가 요구됨.

• Tuberculosis and Respiratory Diseases
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• v.45 no.3
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• pp.536-545
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• 1998

Background: The studies on prediction equations of pulmonary function parameters for adults in Korea have been performed in a reference population mainly consisted of young and middle ages. So they included a relatively few elderly who conducted pulmonary function test frequently in clinic. We established prediction equations of pulmonary function parameters for healthy adults over 50 years old in rural area and compared this results with those of other studies. Therefore we attempted to consider normative values of pulmonary function tests for elderly in Korea. Method: Five hundred thirty-three women and men over 50 years old in rural area were participated. A "healthy" subgroup of 110 women and 32 men were identified by excluding those who had conditions that negatively influenced pulmonary function. We derived prediction equations for FVC, $FEV_1$ and $FEV_1%$ by multiple linear regression method from their age, heights and weights in each sex. Results: Prediction equations for FVC and $FEV_1$ in each sex were derived as follows Male; FVC (L)=0.02488Height(cm)-0.0269Age(years)+0.493 $FEV_1(L)$=0.01874Weight(kg)-0.0282Age(years)+2.906 Female; FVC(L)=0.02160Height(cm)-0.0192Age(years)-0.0125 $FEV_1(L)$=0.01720Height(cm)-0.0194Age(years)+0.3890 Prediction equations for $FEV_1%$ were not derived because $FEV_1%$ didn't have statistically significant terms. Comparing Predicted values that were calculated by substitution into the equations of various studies of mean values of age, heights and weights from this study, FVC and $FEV_1$ values in men of this study were lower than those of other studies. In women, FVC and $FEV_1$ values of this study were as similar as or lower than those of the study conducted for healthy elderly blacks in U.S.A respectively. Conclusion: We have got prediction equations of pulmonary function parameters which were driven from forced expiratory spirogram in adults over 50 years old in rural area. Predicted values of this study were lower than those of other studies which were conducted in Korea. So we consider that the study for spirometry reference values for elderly Korean using the method compatible with ATS recommendation need to be conducted more frequently forward.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.3
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• pp.365-372
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• 2013

In this study, a statistical method for evaluating the fatigue life of a vehicle muffler was used to obtain reliable fatigue data using a limited number of specimens. Cyclic bending tests were conducted using specimens manufactured to be exactly the same as the mufflers installed in cars that are currently in use. To estimate the fatigue life by comparing the data obtained during the fatigue tests, the most suitable probability density function for the normal, lognormal, and Weibull distributions was selected. A goodness-of-fit test was performed on the probability distributions, and then a Weibull distribution using the least square method was selected. By using the selected Weibull distribution, the probability-moment-life curves (P-M-N curve) reflecting the fatigue characteristics were suggested as the data for the reliable design of a muffler.

• Journal of Korean Society of Forest Science
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• v.80 no.4
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• pp.420-426
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• 1991

This study was conducted to provide fundamental information to make rational management planning in eastern seacoast forest, mainly composed of black pine (Pinus Thunbergii), Kangweon Province. Diameter distribution was estimated by the method of Weibull distribution. The results were as fallows ; 1. Average diameter in the eastern seacoast forests of Kangweon Province was 10.3cm, and the average D. B. H, of 16 study sites ranged from 6.9 to 14.6cm. 2. Parameters of the Weibull distribution were estimated in each study sites and the estimated parameters of the all study forests were a=5, b=5.6997 and c=1.4079. 3. Tested by Kolmogorov-Smirnov method for the significant differences between actual and estimated diameter distribution, the result showed that estimated values were well fitted to the actual ones at 5% significance level.

• Analytical Science and Technology
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• v.29 no.1
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• pp.29-34
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• 2016

This study explores the means by which MX can be effectively extracted from chlorinated water 3-Chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone (MX), a potent mutagen commonly found in chlorinated drinking water at concentrations of up to a few hundred ng/L, was quantitatively determined using sample enrichment followed by liquid-liquid extraction (LLE), derivatization to methylated form, and analysis with GC-MS. A 4-L water sample was enriched to a concentration of 0.4 L using a vacuum rotary evaporator at 30 ℃. MX in the water was extracted using ethyl acetate (100 mL × 2) as a solvent and MX in the extract was methylated with 10 % H₂SO₄ in methanol. MX was recovered at a rate of 73.8 %, which was higher than that (38.1 %) for the resin adsorption method. The limit of quantification and repeatability (as relative standard deviation) were estimated to be 10 ng/L and 2.2 %, respectively. This result suggested that LLE can be used for the determination of MX in chlorinated water as an alternative to more time-consuming resin adsorption method.

• Magazine of the Korean Society of Agricultural Engineers
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• v.44 no.5
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• pp.41-53
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• 2002

This study was conducted to derive the regional design rainfall by the regional frequency analysis based on the regionalization of the precipitation suggested by the first report of this project. According to the regions and consecutive durations, optimal design rainfalls were derived by the regional frequency analysis for L-moment in the second report of this project. Using the LH-moment ratios and Kolmogorov-Smirnov test, the optimal regional probability distribution was identified to be the Generalized extreme value (GEV) distribution among applied distributions. regional and at-site parameters of the GEV distribution were estimated by the linear combination of the higher probability weighted moments, LH-moment. Design rainfall using LH-moments following the consecutive duration were derived by the regional and at-site analysis using the observed and simulated data resulted from Monte Carlo techniques. Relative root-mean-square error (RRMSE), relative bias (RBIAS) and relative reduction (RR) in RRMSE for the design rainfall were computed and compared in the regional and at-site frequency analysis. Consequently, it was shown that the regional analysis can substantially more reduce the RRMSE, RBIAS and RR in RRMSE than at-site analysis in the prediction of design rainfall. Relative efficiency (RE) for an optimal order of L-moments was also computed by the methods of L, L1, L2, L3 and L4-moments for GEV distribution. It was found that the method of L-moments is more effective than the others for getting optimal design rainfall according to the regions and consecutive durations in the regional frequency analysis. Diagrams for the design rainfall derived by the regional frequency analysis using L-moments were drawn according to the regions and consecutive durations by GIS techniques.